Understanding Thyroid Problems

Through the hormones it produces, the thyroid gland influences almost all of the metabolic processes in your body.  Thyroid disorders can range from a small, harmless goiter (enlarged gland) that needs no treatment to life-threatening cancer.  The most common thyroid problems involve abnormal production of thyroid hormones.  Too much of these vital body chemicals results in a condition known as hyperthyroidism.  Insufficient hormone production leads to hypothyroidism.

Although the effects can be unpleasant or uncomfortable, most thyroid problems can be managed well if properly diagnosed and treated.

What Causes Thyroid Problems?

All types of hyperthyroidism are due to an overproduction of thyroid hormones, but the condition can occur in several ways:

• Graves’ disease: The production of too much thyroid hormone.
• Toxic adenomas: Nodules develop in the thyroid gland and begin to secrete thyroid hormones, upsetting the body’s chemical balance; some goiters may contain several of these nodules. 
• Subacute thyroiditis: inflammation of the thyroid causes the gland to “leak” excess hormones, resulting in temporary hyperthyroidism that generally lasts a few weeks but may persist for months. 
• Pituitary gland malfunctions or cancerous growths in the thyroid gland: Although rare, hyperthyroidism can also develop from these causes.

Hypothyroidism, by contrast, stems from an underproduction of thyroid hormones.  Since your body’s energy production requires certain amounts of thyroid hormones, a drop in hormone production leads to lower energy levels. Causes of hypothyroidism include these:

• Hashimoto’s thyroiditis: In this autoimmune disorder, the body attacks thyroid tissue.  The tissue eventually dies and stops producing hormones.  
• Removal of the thyroid gland: The thyroid may be surgically removed or chemically destroyed as treatment for hyperthyroidism. 
• Exposure to excessive amounts of iodide: Cold and sinus medicines, the heart medicine amiodarone, or certain contrast dyes given before some X-rays may expose you to too much iodine. You may be at greater risk for developing hypothyroidism, especially if you have had thyroid problems in the past. 
• Lithium: This drug has also been linked as a cause of hypothyroidism. 

Untreated for long periods of time, hypothyroidism can bring on a myxedema coma, a rare but potentially fatal condition that requires immediate hormone injections.

Hypothyroidism poses a special danger to newborns and infants.  A lack of thyroid hormones in the system at an early age can lead to the development of cretinism (mental retardation) and dwarfism (stunted growth).  Most infants now have their thyroid levels checked routinely soon after birth.  If they are hypothyroid, treatment begins immediately.  In infants, as in adults, hypothyroidism can be due to these causes:

• A pituitary disorder
• A defective thyroid
• Lack of the gland entirely

A hypothyroid infant is unusually inactive and quiet, has a poor appetite and sleeps for excessively long periods of time.

Cancer of the thyroid gland is quite rare and occurs in less than 10% of thyroid nodules.  You might have one or more thyroid nodules for several years before they are determined to be cancerous.  People who have received radiation treatment to the head and neck earlier in life, possibly as a remedy for acne, tend to have a higher-than-normal propensity for thyroid cancer.

Cholesterol and Triglycerides Tests

Cholesterol and triglyceride tests are blood tests that measure the total amount of fatty substances (cholesterol and triglycerides) in the blood.

Cholesterol travels through the blood attached to a protein. This cholesterol-protein package is called a lipoprotein. Lipoprotein analysis (lipoprotein profile or lipid profile) measures blood levels of total cholesterol, LDL cholesterol,HDL cholesterol, and triglycerides.

• Cholesterol. The body uses cholesterol to help build cells and producehormones. Too much cholesterol in the blood can build up along the inside of the artery walls, forming what is known as plaque. Large amounts of plaque increase your chances of having a heart attack or stroke.
• HDL (high-density lipoprotein) cholesterol helps remove fat from the body by binding with it in the bloodstream and carrying it back to the liver for disposal. It is sometimes called “good” cholesterol. A high level of HDL cholesterol may lower your chances of developing heart disease or stroke.
• LDL (low-density lipoprotein) cholesterol carries mostly fat and only a small amount of protein from the liver to other parts of the body. It is sometimes called “bad cholesterol.” A high LDL cholesterol level may increase your chances of developing heart disease.
• VLDL: (very low-density lipoprotein) cholesterol contains very little protein. The main purpose of VLDL is to distribute the triglyceride produced by your liver. A high VLDL cholesterol level can cause the buildup of cholesterol in your arteries and increases your risk of heart disease and stroke.
• Triglycerides are a type of fat the body uses to store energy. Only small amounts are found in the blood. Having a high triglyceride level along with a high LDL cholesterol may increase your chances of having heart disease more than having only a high LDL cholesterol level.

Some medical experts recommend routine cholesterol and triglyceride testing to screen for problems that affect the way cholesterol is produced, used, carried in the blood, or disposed of by the body. Others may choose to routinely measure only total cholesterol and HDL levels.

Cholesterol and triglyceride testing is done:

• As part of a routine physical exam to screen for a lipid disorder.
• To check your response to medicines used to treat lipid disorders.
• To help determine your chances of having of heart disease, especially if you have other risk factors for heart disease or symptoms that suggest heart disease is present.
• If you have unusual symptoms, such as yellow fatty deposits in the skin (xanthomas), which may be caused by a rare genetic disease that causes very high cholesterol levels.

Risks

There is very little chance of a problem from having blood sample taken from a vein.

• You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
• In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
• Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your health professional before your blood sample is taken.

• An HDL level of 60 mg/dL (1.5 mmol/L) or higher protects against heart disease.
• HDL cholesterol levels of 40 mg/dL (1.0 mmol/L) or lower increase your risk of developing heart disease, especially if you also have high total cholesterol levels.
• Very high cholesterol and triglyceride levels may be caused by an inherited form of high cholesterol (hypercholesterolemia or hyperlipidemia).
• If you have a very high risk of having a heart attack, your doctor may want your LDL level to be less than 70 mg/dL. You have a very high risk if you smoke and have coronary artery disease, or if you have coronary artery disease anddiabetes, acute coronary syndrome, or metabolic syndrome.

Many conditions can affect cholesterol and triglyceride levels. Your health professional will talk with you about any abnormal results that may be related to your other health problems.

Calcium (Ca) in Blood

A test for calcium in the blood checks the calcium level in the body that is not stored in the bones. Calcium is the most common mineral in the body and one of the most important. The body needs it to build and fix bones and teeth, help nerves work, make muscles squeeze together, help blood clot, and help the heart to work. Almost all of the calcium in the body is stored in bone. The rest is found in the blood.

Normally the level of calcium in the blood is carefully controlled. When blood calcium levels get low (hypocalcemia), the bones release calcium to bring it back to a good blood level. When blood calcium levels get high (hypercalcemia), the extra calcium is stored in the bones or passed out of the body in urine and stool. The amount of calcium in the body depends on the amount of:

• Calcium you get in your food.
• Calcium and vitamin D your intestines absorb.
• Phosphate in the body.
• Certain hormones, including parathyroid hormone, calcitonin, and estrogen in the body.

Vitamin D and these hormones help control the amount of calcium in the body. They also control the amount of calcium you absorb from food and the amount passed from the body in urine. The blood levels of phosphate are closely linked to calcium levels and they work in opposite ways: As blood calcium levels get high, phosphate levels get low and the opposite is true.

It is important to get the right amount of calcium [at least 1000mg a day] in your food because the body loses calcium every day. Foods rich in calcium include dairy products (milk, cheese), eggs, fish, green vegetables, and fruit. Most people who have low or high levels of calcium do not have any symptoms. Calcium levels need to be very high or low to cause symptoms.

Why It Is Done

A blood calcium test may be done:

• To check for problems with the parathyroid glands or kidneys, certain types of cancers and bone problems, inflammation of the pancreas (pancreatitis), andkidney stones. Abnormal results on an electrocardiogram (EKG) test may be caused by high or low calcium levels.
• To see if your symptoms may be caused by a very low calcium level in the blood. Such symptoms may include muscle cramps and twitching, tingling in the fingers and around the mouth, muscle spasms, confusion, or depression.
• To see if your symptoms may be caused by a very high calcium level in the blood. Such symptoms may include weakness, lack of energy, not wanting to eat, nausea and vomiting, constipation, urinating a lot, belly pain, or bone pain.
• As part of a routine blood test.

A blood calcium test cannot be used to check for a lack of calcium in your diet or for the loss of calcium from the bones (osteoporosis). The body can have normal calcium levels even if your diet does not have enough calcium in it. Other tests, such as bone mineral density, check the amount of calcium in the bones.

Risks

There is very little chance of a problem from having blood sample taken from a vein.

• You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
• In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
• Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Results

A test for calcium in the blood checks the calcium level in the body that is not stored in the bones.

High values

• High levels of calcium in the blood may be caused by being on bed rest for a long time, hyperparathyroidism, kidney disease, tuberculosis, or cancer that has spread to the bones. Certain cancers can make a substance that causes high blood calcium levels.
• High levels of calcium in the blood can be caused by eating a diet with too much vitamin D, vitamin A, or calcium. Eating large amounts of milk products or taking too many calcium medicines, such as antacids or vitamin supplements, can also cause high blood calcium levels.
• High levels of calcium in the blood can be caused by dehydration, sarcoidosis, chronic liver or kidney problems, Paget’s disease, and Addison’s disease.
• In rare cases, hyperthyroidism may cause high blood calcium levels.
• In a person with cancer, a high blood calcium level is an emergency. Treatment must be started immediately to prevent the person from becoming confused and dehydrated.

Low values

• Low levels of calcium in the blood can be caused by parathyroid gland(hypoparathyroidism) problems, problems with your intestines that stop your body from absorbing calcium and other nutrients from food (malabsorption syndrome), bone problems, kidney disease, acute pancreatitis, or low amounts of the protein albumin in the blood (hypoalbuminemia).
• Low ionized calcium levels may be caused by low magnesium levels.
• Pregnant women and older men may also have low calcium levels.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Drinking too much milk or using too much antacid, calcium salt, or calcium supplement.
• Taking medicines, such as diuretics, acetazolamide (Diamox), albuterol, estrogen, birth control pills, corticosteroids, and some medicines that controlseizures.
• Taking too much vitamin D, lithium, laxatives, theophylline, or aspirin.
• Having many blood transfusions in a short period of time.

What To Think About

• More than one blood test may be needed to see whether blood calcium levels are too high.
• Low blood levels of calcium may be caused by low levels of protein (albumin) in the blood, because about half of all calcium in the blood is attached to albumin. For this reason, an ionized calcium level (which is not attached to albumin) and a blood albumin level may also be measured. For more information, see the medical test Total Serum Protein.
• Other tests that may be done to find the cause of abnormal blood calcium levels include blood tests for parathyroid hormone (PTH), chloride, acid phosphatase, alkaline phosphatase, and vitamin D. For more information, see the medical testsParathyroid Hormone and Alkaline Phosphatase.
• Since calcium affects how the heart works, a high or low blood calcium level may be the cause of abnormal results on an electrocardiogram (EKG) test. A blood calcium test will be done to help find the cause of the abnormal EKG results.
• Calcium levels can also be checked in the urine. 

Phosphate in Blood

A phosphate test measures the amount of phosphate in a blood sample. Phosphate is a charged particle (ion) that contains the mineral phosphorus. The body needs phosphorus to build and repair bones and teeth, help nerves function, and make muscles contract. Most (about 85%) of the phosphorus contained in phosphate is found in bones. The rest of it is stored in tissues throughout the body.

The kidneys help control the amount of phosphate in the blood. Extra phosphate is filtered by the kidneys and passes out of the body in the urine. A high level of phosphate in the blood is usually caused by a kidney problem.

The amount of phosphate in the blood affects the level of calcium in the blood. Calcium and phosphate in the body react in opposite ways: As blood calcium levels rise, phosphate levels fall. But this relation between calcium and phosphate may be disrupted by some diseases or infections. For this reason, phosphate and calcium levels are usually measured at the same time.

Why It Is Done

A test to measure phosphate in blood may be done to:

• Check phosphate levels if you have kidney disease or bone disease.
• Help find problems with certain glands, such as the parathyroid glands.

High values

High phosphate levels may be caused by:

• Kidney disease, underactive parathyroid glands (hypoparathyroidism),acromegaly, rhabdomyolysis, healing fractures, untreated diabetic ketoacidosis, or certain bone diseases.
• Too much vitamin D in the body.
• A decrease in magnesium levels.
• Pregnancy.

Low values

Low phosphate levels may be caused by:

• Hyperparathyroidism, certain bone diseases (such as osteomalacia), lack of vitamin D, severe burns, or some kidney or liver diseases.
• Severe malnutrition or starvation.
• A condition such as sprue that prevents the intestines from absorbing nutrients properly.
• Alcohol dependence.
• High calcium levels.

Amylase

An amylase test measures the amount of this enzyme in a sample of blood taken from a vein or in a sample of urine.

Normally, only low levels of amylase are found in the blood or urine. However, if thepancreas or salivary glands become damaged or blocked, more amylase is usually released into the blood and urine. In the blood, amylase levels rise for only a short time. In the urine, amylase may remain high for several days.

Why It Is Done

A test for amylase is done to:

• Find pancreatitis and other pancreatic diseases.
• See if the treatment for pancreatitis and other pancreatic diseases is working.
• Check swelling and inflammation of the salivary glands.

High values

Values may be high because of:

• Inflammation of the pancreas (pancreatitis) or cancer of the pancreas.
• Inflammation of the salivary glands, such as mumps.
• Blockage of or severe damage to the intestines (bowel infarction).
• A stomach ulcer that has caused a hole in the stomach wall.
• Gallstones that are causing pancreatitis.
• Cystic fibrosis.
• Pregnancy and diabetic ketoacidosis.
• A ruptured ectopic pregnancy.
• Macroamylasemia, an uncommon and harmless condition in which amylase is bound to a protein in the blood. This condition can cause amylase levels to be either high or low.

Low values

Values may be low because of an uncommon and harmless condition called macroamylasemia, severe liver disease, pregnancy, preeclampsia, or advanced cystic fibrosis.

What Affects the Test

Factors that can interfere with your test or the accuracy of the results include:

• Medicines, including narcotics such as codeine and morphine, birth control pills,diuretics, indomethacin (Indocin), and blood-thinning medicines, such as warfarin (Coumadin) and aspirin.
• Hepatitis, cirrhosis, or extensive damage to the pancreas.
• Chronic pancreatitis, which may be present even though amylase levels are low.
• Blood in the urine. If you are a woman who has menstrual periods, you may need to schedule a urine test for amylase when you are not having your period.
• Drinking a large amount of alcohol before the test.
• Saliva, which contains large amounts of amylase. Coughing, sneezing, or even talking over an uncovered urine or blood specimen can contaminate the specimen and artificially increase amylase values.
• Chronic kidney disease, which may cause high levels when the kidneys are no longer able to remove amylase from the blood.

What To Think About

• Pancreatitis usually causes levels of amylase in the urine to remain high for several days longer than blood amylase levels.
• Babies have little or no amylase at birth. By the end of the first year, a baby’s amylase level is the same as an adult’s level.
• Lipase is an enzyme produced only by the pancreas. A lipase test may be done at the same time as an amylase test when pancreatitis is suspected. For more information, see the medical test Lipase.
• Occasionally, a test that compares urine amylase with creatinine (a renal clearance ratio) may be done to help diagnose pancreatitis. For more information, see the medical test Creatinine.

Cardiac Enzyme

Measure the levels of the enzyme creatine phosphokinase (CPK, CK) and the protein troponin (TnI, TnT) in the blood. Low levels of these enzymes and proteins are normally found in your blood, but if your heart muscle is injured, such as from a heart attack, the enzymes and proteins leak out of damaged heart muscle cells, and their levels in the bloodstream rise.

Because some of these enzymes and proteins are also found in other body tissues, their levels in the blood may rise when those other tissues are damaged. Cardiac enzyme studies must always be compared with your symptoms, your physical examination findings, and electrocardiogram (EKG, ECG) results.

Why It Is Done

Cardiac enzyme studies are done to:

• Determine whether you are having a heart attack or a threatened heart attack (unstable angina) if you have chest pain, shortness of breath, nausea, sweating, and abnormal electrocardiography results.
• Check for injury to the heart after bypass surgery.
• Determine if a procedure, such as percutaneous coronary intervention (PCI), or a medicine to dissolve the blockage (thrombolytic medicine) has successfully restored blood flow through a blocked coronary artery.

isks

There is very little chance of a problem from having blood sample taken from a vein.

• You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
• In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
• Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin) and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Results

Cardiac enzyme studies measure the levels of the enzyme creatine phosphokinase (CPK, CK) and the protein troponin (TnI, TnT) in the blood.

Test results are usually available within an hour.

Values and units for reporting the results of cardiac enzyme tests vary considerably from lab to lab. The values listed below can be used as a general guide. Check with your lab or doctor for specific values.

Troponin (TnI and TnT)

Normal:	TnI: Less than 0.3 micrograms per liter (mcg/L) TnT: Less than 0.1 mcg/L
Abnormal:	Elevated troponin may be present when you have heart muscle injury. Blood levels of troponin typically rise within 4 to 6 hours after a heart attack, reach their highest levels within 10 to 24 hours, and fall to normal levels within 10 days.

 

Total CPK (creatine phosphokinase)

Normal:	Men:	55–170 international units per liter (IU/L)
	Women:	30–135 IU/L
Abnormal:	CPK levels generally rise within 4 to 8 hours after a heart attack, reach their highest levels within 12 to 24 hours, then return to normal within 3 to 4 days.

 

CPK-MB

Normal:	Less than 3.0 nanograms per milliliter (ng/mL) (0% of total CPK)
Abnormal:	CPK-MB is found in large amounts in the heart muscle. A CPK-MB greater than 3.0 ng/mL may be present when you have muscle damage caused by a heart attack. Blood levels of CPK-MB typically rise within 2 to 6 hours after a heart attack, reach their highest levels within 12 to 24 hours, and fall to normal levels within 3 days.
	An ongoing high level of CPK-MB levels after 3 days may mean that a heart attack is progressing and more heart muscle is being damaged.

 

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Other diseases, such as muscular dystrophy, certain autoimmune diseases, andReye’s syndrome.
• Other heart conditions, such as myocarditis and some forms of cardiomyopathy.
• Emergency measures to treat heart problems, such as CPR, cardioversion, or defibrillation.
• Medicines, especially injections into muscles (IM injections).
• Cholesterol-lowering medicines (statins).
• Heavy alcohol use.
• Recent strenuous exercise.
• Kidney failure.
• Recent surgery or serious injury.

What To Think About

• Cardiac enzyme and protein levels must always be compared with your symptoms, medical history, physical examination, and electrocardiography (EKG, ECG) results.
• Troponin is an accurate method for quickly diagnosing heart attack, but because it takes up to 6 hours for the troponin level to rise, it can be low or negative at first. Troponin is more specific to heart muscle and remains in the bloodstream longer than CPK.
• CPK-MB, which is found in large amounts in damaged heart muscle, is a more specific way to estimate the amount of heart muscle damage than total CPK. The total CPK enzyme level can be elevated from vigorous exercise, intramuscular injections, crush injuries to muscles, muscular dystrophy, or muscle inflammation.
• Another protein, myoglobin, may be tested along with cardiac enzymes to diagnose a heart attack.

Liver Function Test II

An alkaline phosphatase (ALP) test measures the amount of theenzyme ALP in the blood. ALP is made mostly in the liver and in bone with some made in the intestines and kidneys. It also is made by the placenta of a pregnant woman.

The liver makes more ALP than the other organs or the bones. Some conditions cause large amounts of ALP in the blood. These conditions include rapid bone growth (during puberty), bone disease (osteomalacia or Paget’s disease), or a disease that affects how much calcium is in the blood (hyperparathyroidism), or damaged liver cells.

If the ALP level is high, more tests may be done to find the cause.

Why It Is Done

A test for alkaline phosphatase (ALP) is done to:

• Check for liver disease or damage to the liver. Symptoms of liver disease can include jaundice, belly pain, nausea, and vomiting. An ALP test may also be used to check the liver when medicines that can damage the liver are taken.
• Check bone problems (sometimes found on X-rays), such as rickets, osteomalacia, bone tumors, Paget’s disease, or too much of the hormone that controls bone growth (parathyroid hormone). The ALP level can be used to check how well treatment for Paget’s disease is working.

Risks

There is very little chance of a problem from having blood sample taken from a vein.

• You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
• In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
• Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Results

An alkaline phosphatase (ALP) test measures the amount of the enzyme ALP in the blood.

Normal

Normal values may vary from lab to lab.

Alkaline phosphatase

Adults:					30–126 units per liter (U/L) or 0.5–2.0 microkat/liter (mckat/L)
Children:					30–300 U/L or 0.5–5.0 mckat/L

Women in the third trimester of pregnancy have high ALP levels because theplacenta makes ALP. Children normally have much higher ALP than adults because rapid bone growth is normal in children and bones make ALP.

High values

• Very high levels of ALP can be caused by liver problems, such as hepatitis, blockage of the bile ducts (obstructive jaundice), gallstones, cirrhosis, liver cancer, or cancer that has spread (metastasized) to the liver from another part of the body.
• High ALP levels can be caused by bone diseases, such as Paget’s disease,osteomalacia, rickets, bone tumors, or tumors that have spread from another part of the body to the bone, or by overactive parathyroid glands(hyperparathyroidism). Normal healing of a bone fracture can also raise ALP levels.
• Heart failure, heart attack, mononucleosis, or kidney cancer can raise ALP levels. A serious infection that has spread through the body (sepsis) can also raise ALP levels.

Low values

Conditions that lead to malnutrition (such as celiac disease) or are caused by a lack of nutrients in the diet (such as scurvy) can cause low ALP levels.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Taking medicines that may damage the liver, such as some antibiotics, birth control pills, long-term aspirin use, and oral diabetes medicines.
• Being pregnant. Women in the third trimester of pregnancy have high ALP levels because the placenta makes ALP.
• Going through menopause. Postmenopausal women may have higher ALP levels than women who still have menstrual cycles.
• Your age. Children normally have much higher ALP levels than adults because rapid bone growth is normal in children and bones make ALP.
• Using alcohol.

What To Think About

• If the ALP level is high, other tests may be done to determine whether a liver or bone problem is present.
• If liver disease is suspected, more blood tests, an ultrasound, or a CT scan are generally recommended to find the problem.
• Other tests to check liver function, such as alanine aminotransferase, aspartate aminotransferase, and bilirubin, are often done at the same time as an alkaline phosphatase (ALP) test. For more information, see the medical tests Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), and Bilirubin.
• Gamma glutamyl transferase (GGT), or gamma glutamyl transpeptidase, may be measured in the blood to check the difference between bone ALP and liver ALP. High levels of GGT are present when the liver is damaged but not present with bone disease. A high level of GGT may be caused by alcohol use or may mean that blocked bile ducts are causing inflammation. The level of GGT may be high with the use of certain medicines, such as phenytoin and phenobarbital. In some medical centers, a test that measures a substance called 5-nucleotidase is done instead of the GGT test because it is better at finding liver disease.

An alanine aminotransferase (ALT) test measures the amount of thisenzyme in the blood. ALT is found mainly in the liver, but also in smaller amounts in the kidneys, heart, muscles, and pancreas. ALT formerly was called serum glutamic pyruvic transaminase (SGPT).

ALT is measured to see if the liver is damaged or diseased. Low levels of ALT are normally found in the blood. But when the liver is damaged or diseased, it releases ALT into the bloodstream, which makes ALT levels go up. Most increases in ALT levels are caused by liver damage.

The ALT test is often done along with other tests that check for liver damage, including aspartate aminotransferase (AST), alkaline phosphatase, lactate dehydrogenase (LDH), and bilirubin. Both ALT and AST levels are reliable tests for liver damage.

Why It Is Done

The alanine aminotransferase (ALT) test is done to:

• Identify liver disease, especially cirrhosis and hepatitis caused by alcohol, drugs, or viruses.
• Help check for liver damage.
• Find out whether jaundice was caused by a blood disorder or liver disease.
• Keep track of the effects of cholesterol-lowering medicines and other medicines that can damage the liver.

Risks

There is very little chance of a problem from having blood sample taken from a vein.

• You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
• In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
• Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicines, tell your doctor before your blood sample is taken.

Results

An alanine aminotransferase (ALT) test measures the amount of this enzyme in the blood. Results are usually available within 12 hours.

Normal

Normal results may vary from lab to lab.

Alanine aminotransferase

4–36 units per liter (U/L) or 0.07–0.62 microKat/L

High values

Very high levels of ALT may be caused by:

• Recent or severe liver damage, such as viral hepatitis.
• Lead poisoning.
• Drug reactions.
• Exposure to carbon tetrachloride.
• Decay of a large tumor (necrosis).
• Shock.

Mildly or moderately high ALT levels may be caused by:

• Mononucleosis.
• Hepatitis. The ALT level in a person with hepatitis can be 20 times the normal value.
• Alcohol abuse. People who drink excessive amounts of alcohol and take acetaminophen (such as Tylenol) can have high ALT blood levels.
• Mildly elevated levels of ALT may occur in people who are growing quickly, especially young children.

Slightly high levels ALT levels may be caused by:

• Fatty deposits in the liver.
• Many medicines, such as statins, antibiotics, chemotherapy, aspirin, narcotics, and barbiturates.
• Long-term (chronic) diseases that affect the liver, such as cirrhosis.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Taking medicines. Talk with your doctor about all the prescription and nonprescription medicines you are taking. You may be instructed to stop taking your medicines for several days before the test.
• Taking some herbs and natural products, such as echinacea and valerian.
• Strenuous exercise, injury to a muscle, or injections into a muscle.
• Recent cardiac catheterization or surgery.

What To Think About

• The alanine aminotransferase (ALT) value is often used along with the results of the aspartate aminotransferase (AST) test to obtain the AST to ALT ratio. This value can often help determine whether there is damage to the liver related to alcohol abuse. For more information, see the medical test Aspartate Aminotransferase (AST).
• In children with acute lymphocytic leukemia (ALL), very high ALT levels may mean that the disease is likely to progress rapidly.
• Many different conditions can raise ALT blood levels, so other testing is usually needed to interpret an abnormal ALT result.

An aspartate aminotransferase (AST) test measures the amount of this enzyme in the blood. AST is normally found in red blood cells, liver, heart, muscle tissue, pancreas, and kidneys. AST formerly was called serum glutamic oxaloacetic transaminase (SGOT).

Low levels of AST are normally found in the blood. When body tissue or an organ such as the heart or liver is diseased or damaged, additional AST is released into the bloodstream. The amount of AST in the blood is directly related to the extent of the tissue damage. After severe damage, AST levels rise in 6 to 10 hours and remain high for about 4 days.

The AST test may be done at the same time as a test for alanine aminotransferase, or ALT. The ratio of AST to ALT sometimes can help determine whether the liver or another organ has been damaged. Both ALT and AST levels can test for liver damage.

Why It Is Done

An aspartate aminotransferase (AST) test is done to:

• Check for liver damage.
• Help identify liver disease, especially hepatitis and cirrhosis. Liver disease may produce symptoms such as pain in the upper abdomen, nausea, vomiting, and sometimes jaundice.
• Check on the success of treatment for liver disease.
• Find out whether jaundice was caused by a blood disorder or liver disease.
• Keep track of the effects of cholesterol-lowering medicines and other medicines that can damage the liver.

Risks

There is very little chance of a problem from having blood sample taken from a vein.

• You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
• In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
• Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Results

An aspartate aminotransferase (AST) test measures the amount of this enzyme in the blood. Results are usually available within 12 hours.

Normal

Normal values may vary from lab to lab.

Aspartate aminotransferase (AST)

8–35 units per liter (U/L) or 0.14–0.58 microKat/L

High values

Very high levels of AST may be caused by:

• Recent or severe liver damage, such as hepatitis caused by a viral infection or drug reaction.
• Decay of a large tumor (necrosis).
• Shock.

Moderately high levels of AST may be caused by:

• Long-term (chronic) diseases that affect the liver, such as cirrhosis.
• A heart attack or heart failure.
• Alcohol abuse.
• Having taken high doses of vitamin A.
• Kidney or lung damage.
• Mononucleosis.
• Duchenne muscular dystrophy.
• Some types of cancer.
• A rare autoimmune disease that affects muscles (myositis).

Slightly high levels of AST may be caused by:

• Fatty deposits in the liver.
• Many medicines, such as statins, antibiotics, chemotherapy, aspirin, narcotics, and barbiturates.
• Alcohol abuse. People who drink excessive amounts of alcohol and take acetaminophen (such as Tylenol) can have high AST blood levels.

AST levels may be high when a disease first develops, which is often when tissue damage is most severe. Decreasing levels of AST in the blood may be a sign of recovery from the disease or injury.

Many other conditions, including severe burns, traumatic injuries, pulmonary embolism, or heat exhaustion and heatstroke, and ingestion of poisonous mushrooms may cause elevated AST levels.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Taking medicines. Talk with your doctor about all the prescription and nonprescription medicines you are taking. You may be instructed to stop taking your medicines for several days before the test.
• Taking large doses of vitamin A.
• Taking some herbs and natural products, such as echinacea and valerian.
• Strenuous exercise, injury to a muscle, or injections into a muscle.
• Recent cardiac catheterization or surgery.

What To Think About

• The aspartate aminotransferase (AST) test is more effective than the alanine aminotransferase (ALT) test for detecting liver damage caused by alcohol abuse. The AST to ALT ratio may sometimes help determine if liver damage is related to alcohol dependence. For more information, see the medical test Alanine Aminotransferase (ALT).
• Many different conditions can raise AST blood levels, so other testing is usually needed to interpret an abnormal AST result.

 

Liver function tests

Some blood tests are used to determine whether your liver is damaged or inflamed. Although these tests help your doctor evaluate how well your liver is working, they cannot tell if you have hepatitis C.

Tests that assess liver function

Your doctor may do tests to measure certain chemicals produced by the liver. These tests can help your doctor check how well your liver is working. Tests may measure:

• Bilirubin.
• Albumin.
• Prothrombin time (a measure of blood clotting). It may also be called International Normalized Ratio (INR).

Tests that check for inflammation of the liver (liver enzyme studies)

If you have increased levels of the following, your liver may be damaged:

• Alanine aminotransferase (ALT or SGPT)
• Aspartate aminotransferase (AST or SGOT)

An increased level of alkaline phosphatase (AP) may indicate blockage of bile ducts.

Why It Is Done

Liver tests are done when a medical history or physical exam suggests that something may be wrong with your liver.

These tests can also help diagnose long-term (chronic) infection. Hepatitis C infection is considered chronic when liver enzymes remain elevated for longer than 6 months.

If you are being treated with antiviral therapy, you may have liver tests from time to time to see whether treatment is working.

Results

Findings of liver function tests may include the following:

Normal

All levels are within the normal range.

Abnormal

One or more levels are outside the normal range. Abnormal liver function tests may indicate that your liver is inflamed or is not working normally. This can be a sign that you have a viral infection.

What To Think About

Elevated liver enzymes can be caused by many things other than hepatitis C, such as obesity, hepatitis B, autoimmune hepatitis, certain medicines, or long-term alcohol use. So you will need other tests (such as a hepatitis C antibody blood test or a liver biopsy) to confirm a diagnosis of hepatitis C.

People with chronic hepatitis C have abnormal liver enzyme levels most of the time. But the levels can fluctuate between normal and abnormal throughout the course of the disease.

Liver tests can be used to help you and your doctor develop a treatment plan. Signs that you might need treatment include:

• Liver enzyme levels that remain above normal for longer than 6 months, which is evidence of chronic infection.
• Detectable levels of hepatitis C virus in your blood (positive hepatitis C RNA test). This is a sign of an active infection.
• Evidence of serious liver damage. This is detected with a liver biopsy.

A total serum protein test measures the total amount of protein in the blood. It also measures the amounts of two major groups of proteins in the blood: albumin and globulin.

• Albumin is made mainly in the liver. It helps keep the blood from leaking out of blood vessels. Albumin also helps carry some medicines and other substances through the blood and is important for tissue growth and healing.
• Globulin is made up of different proteins called alpha, beta, and gamma types. Some globulins are made by the liver, while others are made by the immune system. Certain globulins bind with hemoglobin. Other globulins transport metals, such as iron, in the blood and help fight infection. Serum globulin can be separated into several subgroups by serum protein electrophoresis. For more information, see the medical test Serum Protein Electrophoresis.

A test for total serum protein reports separate values for total protein, albumin, and globulin. The amounts of albumin and globulin also are compared (albumin/globulin ratio). Normally, there is a little more albumin than globulin and the ratio is greater than 1. A ratio less than 1 or much greater than 1 can give clues about problems in the body.

Why It Is Done

Albumin is tested to:

• Check how well the liver and kidney are working.
• Find out if your diet contains enough protein.
• Help determine the cause of swelling of the ankles (edema) or abdomen (ascites) or of fluid collection in the lungs that may cause shortness of breath (pulmonary edema).

Globulin is tested to:

• Determine your chances of developing an infection.
• See if you have a rare blood disease, such as multiple myeloma ormacroglobulinemia.

Risks

There is very little chance of a problem from having blood sample taken from a vein.

• You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
• In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
• Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Results

A total serum protein test is a blood test that measures the amounts of totalprotein, albumin, and globulin in the blood. Results are usually available within 12 hours.

Normal

Normal values may vary from lab to lab.

Total serum protein

Total protein:	5.5–9.0 grams per deciliter (g/dL)
Albumin:	3.5–5.5 g/dL
Globulin:	2.0–3.5 g/dL
Albumin/globulin ratio:	Greater than 1.0

High values

High albumin levels may be caused by:

• Severe dehydration.

High globulin levels may be caused by:

• Diseases of the blood, such as multiple myeloma, Hodgkin’s lymphoma,leukemia, macroglobulinemia, or hemolytic anemia.
• An autoimmune disease, such as rheumatoid arthritis, lupus, autoimmunehepatitis, or sarcoidosis.
• Kidney disease.
• Liver disease.
• Tuberculosis.

Low values

Low albumin levels may be caused by:

• A poor diet (malnutrition).
• Severe burns.
• Kidney disease.
• Liver disease.
• An autoimmune disease, such as systemic lupus erythematosus (SLE) or rheumatoid arthritis.
• Gastrointestinal malabsorption syndromes, such as sprue or Crohn’s disease.
• Hodgkin’s lymphoma.
• Uncontrolled diabetes.
• Hyperthyroidism.
• Heart failure.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Taking medicines, such as corticosteroids, estrogens, male sex hormones(called androgens), growth hormone, or insulin.
• Injuries or infections.
• Prolonged bed rest, such as during a hospital stay.
• A long-term (chronic) illness, especially if the disease interferes with what you are able to eat or drink.
• Being pregnant.

What To Think About

• If you have abnormal globulin levels, another test called serum protein electrophoresis is often done. This test measures specific groups of proteins in the blood. For more information, see the medical test Serum Protein Electrophoresis.
• Damaged liver cells lose their ability to make protein. But previously produced protein may stay in the blood for 12 to 18 days, so it takes about 2 weeks for damage to the liver to show up as decreased serum protein levels. The liver’s ability to make protein may be used to predict the course of certain liver diseases.
• Unlike carbohydrates and fats, proteins are not stored in the body. They are continuously broken down (metabolized) into amino acids that can be used to make new proteins, hormones, enzymes, and other compounds needed by the body.
• Protein also can be measured in the urine. For more information, see the medical test Urine Test.

A bilirubin test measures the amount of bilirubin in a blood sample. Bilirubin is a brownish yellow substance found in bile. It is produced when the liver breaks down old red blood cells. Bilirubin is then removed from the body through the stool (feces) and gives stool its normal brown color.

Bilirubin circulates in the bloodstream in two forms:

• Indirect (or unconjugated) bilirubin. This form of bilirubin does not dissolve in water (it is insoluble). Indirect bilirubin travels through the bloodstream to the liver, where it is changed into a soluble form (direct or conjugated).
• Direct (or conjugated) bilirubin. Direct bilirubin dissolves in water (it is soluble) and is made by the liver from indirect bilirubin.

Total bilirubin and direct bilirubin levels are measured directly in the blood, whereas indirect bilirubin levels are derived from the total and direct bilirubin measurements.

When bilirubin levels are high, the skin and whites of the eyes may appear yellow (jaundice). Jaundice may be caused by liver disease (hepatitis), blood disorders (hemolytic anemia), or blockage of the tubes (bile ducts) that allow bile to pass from the liver to the small intestine.

Too much bilirubin (hyperbilirubinemia) in a newborn baby can cause brain damage (kernicterus), hearing loss, problems with the muscles that move the eye, physical abnormalities, and even death. Therefore, some babies who develop jaundice may be treated with special lights (phototherapy) or a blood transfusion to lower their bilirubin levels.

In a newborn baby, the blood sample is usually taken from the heel (heel stick).

Why It Is Done

The bilirubin test is used to:

• Check liver function and watch for signs of liver disease, such as hepatitis orcirrhosis, or the effects of medicines that can damage the liver.
• Find out if something is blocking the bile ducts. This may occur if gallstones, tumors of the pancreas, or other conditions are present.
• Diagnose conditions that cause increased destruction of red blood cells, such as hemolytic anemia or hemolytic disease of the newborn.
• Help make decisions about whether newborn babies with neonatal jaundice need treatment. These babies may need treatment with special lights, called phototherapy. In rare cases, blood transfusions may be needed.

How To Prepare

Adults should not eat or drink for 4 hours before a bilirubin test.

No special preparation is needed for children before having a bilirubin test.

Tell your doctor if you:

• Are taking any medicines.
• Are allergic to any medicines.
• Have had bleeding problems or take blood-thinners, such as aspirin or warfarin (Coumadin).
• Are or might be pregnant.

Normal adult values

Normal values may vary from lab to lab.

Bilirubin levels in adults

Bilirubin type	Bilirubin level
Total bilirubin	0.3–1.0 mg/dL or 5.1–17.0 mmol/L
Direct bilirubin	0.1–0.3 mg/dL or 1.7–5.1 mmol/L
Indirect bilirubin (total bilirubin level minus direct bilirubin level)	0.2–0.8 mg/dL or 3.4–12.0 mmol/L

High values

• High levels of bilirubin in the blood may be caused by:
  • Some infections, such as an infected gallbladder, or cholecystitis.
  • Some inherited diseases, such as Gilbert’s syndrome, a condition that affects how the liver processes bilirubin. Although jaundice may occur in some people with Gilbert’s syndrome, the condition is not harmful.
  • Diseases that cause liver damage, such as hepatitis, cirrhosis, ormononucleosis.
  • Diseases that cause blockage of the bile ducts, such as gallstones or cancer of the pancreas.
  • Rapid destruction of red blood cells in the blood, such as from sickle cell disease or an allergic reaction to blood received during a transfusion (called a transfusion reaction).
  • Medicines that may increase bilirubin levels. This includes many antibiotics, some types of birth control pills, indomethacin (Indocin), phenytoin (Dilantin), diazepam (Valium), and flurazepam (Dalmane).

Low values

Low levels of bilirubin in the blood may be caused by:

• Medicines that may decrease bilirubin levels. This includes vitamin C (ascorbic acid), phenobarbital, and theophylline (Elixophyllin).

Normal values in newborns

Normal values in newborns depend on the age of the baby in hours and whether the baby was premature or full term. Normal values may vary from lab to lab.

Total bilirubin levels in newborns less than 7 days old

Age	Premature baby	Full-term baby
Less than 24 hours	Less than 8.0 mg/dL or less than 137 mmol/L	Less than 6.0 mg/dL or less than 103 mmol/L
Less than 48 hours	Less than 12.0 mg/dL or less than 205 mmol/L	Less than 10.0 mg/dL or less than 170 mmol/L
3 to 5 days	Less than 15.0 mg/dL or less than 256 mmol/L	Less than 12.0 mg/dL or less than 205 mmol/L
7 days or older	Less than 15.0 mg/dL or less than 256 mmol/L	Less than 10.0 mg/dL or less than 170 mmol/L

 

Bilirubin levels that may require treatment in a full-term, healthy baby

Baby’s age	Bilirubin level
24 hours or younger:	More than 10 mg/dL or more than 170 mmol/L
25 to 48 hours:	More than 15 mg/dL or more than 255 mmol/L
49 to 72 hours:	More than 18 mg/dL or more than 305 mmol/L
Older than 72 hours:	More than 20 mg/dL or more than 340 mmol/L

Note: A premature or sick baby with bilirubin levels lower than those listed above may need treatment.

A premature baby’s liver is immature and may not be able to break down bilirubin properly in the blood. This is one of the reasons premature babies are more likely than full-term babies to develop jaundice.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful (except in newborns) include:

• Caffeine, which can lower bilirubin levels.
• Not eating for a long period (fasting), which normally increases indirect bilirubin levels.

What To Think About

• A common cause of jaundice in newborns is a condition called physiologic jaundice. It occurs in healthy babies when they are 1 to 3 days old for several reasons, including the increased breakdown of red blood cells right after birth. It usually disappears on its own within a week without causing problems. However, in some cases, a baby with physiologic jaundice may need treatment with special lights (phototherapy) to prevent serious problems.
• Bilirubin can be measured in amniotic fluid if your doctor thinks that your unborn baby may have a condition that destroys red blood cells (erythroblastosis fetalis). For more information, see the medical test Amniocentesis.
• Bilirubin may also be measured in the urine. Normally urine does not contain any bilirubin. If bilirubin is detected in urine, additional testing may be needed to determine the cause. High amounts of bilirubin in urine may indicate that the bilirubin is not being removed from the body by the liver.
• Using a transcutaneous bilirubin test, doctors can screen all newborns for jaundice. They place a device gently against the skin to check bilirubin levels before a baby goes home from the hospital.

Blood Glucose

A blood glucose test measures the amount of a type of sugar, called glucose, in your blood. Glucose comes from carbohydrate foods. It is the main source of energy used by the body. Insulin is a hormone that helps your body’s cells use the glucose. Insulin is produced in the pancreas and released into the blood when the amount of glucose in the blood rises.

Normally, your blood glucose levels increase slightly after you eat. This increase causes your pancreas to release insulin so that your blood glucose levels do not get too high. Blood glucose levels that remain high over time can damage your eyes, kidneys, nerves, and blood vessels.

Several different types of blood glucose tests are used.

• Fasting blood sugar (FBS) measures blood glucose after you have not eaten for at least 8 hours. It often is the first test done to check for diabetes.
• 2-hour postprandial blood sugar measures blood glucose exactly 2 hours after you eat a meal.
• Random blood sugar (RBS) measures blood glucose regardless of when you last ate. Several random measurements may be taken throughout the day. Random testing is useful because glucose levels in healthy people do not vary widely throughout the day. Blood glucose levels that vary widely may indicate a problem. This test is also called a casual blood glucose test.
• Oral glucose tolerance test is used to diagnose prediabetes and diabetes. An oral glucose tolerance test is a series of blood glucose measurements taken after you drink a sweet liquid that contains glucose. This test is commonly used to diagnose diabetes that occurs during pregnancy (gestational diabetes). For more information, see the medical test Gestational Diabetes. This test is not commonly used to diagnose diabetes in a person who is not pregnant.

Why It Is Done

Blood glucose tests are done to:

• Check for diabetes.
• Monitor treatment of diabetes.
• Check for diabetes that occurs during pregnancy (gestational diabetes).
• Determine if an abnormally low blood sugar level (hypoglycemia) is present. A test to measure blood levels of insulin and a protein called C-peptide may be done along with a blood glucose test to determine the cause of hypoglycemia. For more information, see the medical test C-Peptide.

How To Prepare

Fasting blood sugar (FBS)

For a fasting blood sugar test, do not eat or drink anything other than water for at least 8 hours before the blood sample is taken.

If you have diabetes, you may be asked to wait until you have had your blood tested before taking your morning dose of insulin or diabetes medication.

2-hour postprandial blood sugar

For a 2-hour postprandial test, eat a meal exactly 2 hours before the blood sample is taken. A home blood sugar test is the most common way to check 2-hour postprandial blood sugar levels.

Random blood sugar (RBS)

No special preparation is required before having a random blood sugar test.

Risks

There is very little risk of a problem from having blood drawn from a vein.

• You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.
• In rare cases, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.
• Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your health professional before your blood is drawn.

Results

Normal

A blood glucose test measures the amount of a type of sugar, called glucose, in your blood.

Results are often ready in 1 to 2 hours. Glucose levels in a blood sample taken from your vein (called a blood plasma value) may differ a little than glucose levels checked with a finger stick.

Blood glucose

Fasting blood glucose:	70–99 milligrams per deciliter or less than 5.5mmol/L
2 hours after eating (postprandial):	70–145 mg/dL (less than 7.9 mmol/L)
Random (casual):	70–125 mg/dL (less than 7.0 mmol/L)

 

Normal results may vary from lab to lab. Many conditions can change your blood glucose levels. Your health professional will discuss any significant abnormal results with you in relation to your symptoms and medical history.

High values

You may have diabetes. But your doctor will not use just one test result to diagnose you with the condition.

• The American Diabetes Association (ADA) criteria for diagnosing diabetes are met when any of the following results have been repeated on at least two different days:
  • A fasting blood glucose level is 126 mg/dL (7.0 mmol/L) or higher.
  • A 2-hour oral glucose tolerance test result is 200 mg/dL (11.1 mmol/L) or higher. For more information, see the medical test Oral Glucose Tolerance Test.
  • Symptoms of diabetes are present and a random blood glucose test is 200 mg/dL (11.1 mmol/L) or higher. Symptoms of diabetes include increased thirst and frequent urination (especially at night), unexplained increase in appetite, unexplained weight loss, fatigue, erection problems, blurred vision, and tingling or numbness in the hands or feet.
• If your fasting blood glucose level measures in the range of 100 mg/dL (5.5 mmol/L) to 125 mg/dL (6.9 mmol/L), you are considered to have prediabetes(impaired fasting glucose), and you have an increased chance of getting diabetes.
• Other conditions that can cause high blood glucose levels include severe stress,heart attack, stroke, Cushing’s syndrome, medicines such as corticosteroids, or excess production of growth hormone (acromegaly).

Low values

A fasting glucose level below 40 mg/dL (2.2 mmol/L) in women or below 50 mg/dL (2.8 mmol/L) in men that is accompanied by symptoms of hypoglycemia may mean you have an insulinoma, a tumor that produces abnormally high amounts of insulin.

Low glucose levels also may be caused by:

• Addison’s disease.
• Decreased thyroid hormone levels (hypothyroidism).
• A tumor in the pituitary gland.
• Liver disease, such as cirrhosis.
• Kidney failure.
• Malnutrition or an eating disorder, such as anorexia.
• Medicines used to treat diabetes.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Eating or drinking less than 8 hours before a fasting blood test or less than 2 hours before a 2-hour postprandial test.
• Drinking alcohol.
• Illness or emotional stress, smoking, and caffeine.

Taking a medicine, such as birth control pills, medicines used to treat high blood pressure, phenytoin (Dilantin), furosemide (Lasix), triamterene (Dyrenium, Dyazide), hydrochlorothiazide (Esidrix, Hydro Par, Oretic), niacin, propranolol (Inderal), or corticosteroids (prednisone), can cause changes in your test results. Make sure that your doctor knows about any medicines you take and how often you take them.

What To Think About

• Other tests are needed to accurately diagnose diabetes. A blood glucose test may not identify some people with prediabetes or early diabetes. Many experts recommend using a glucose tolerance test if your fasting blood glucose level measures in the range of 100 mg/dL (5.5 mmol/L) to 125 mg/dL (6.9 mmol/L). This range is above the normal range but below the range that indicates diabetes. For more information, see the medical test Oral Glucose Tolerance Test.
• Glucose levels in urine can also be measured. Many people with diabetes have glucose in their urine. But the level in the blood must be very high before glucose can be detected in the urine. For this reason, tests for glucose in urine are not used to diagnose or monitor diabetes. For more information, see the medical testUrine Test.
• If you have diabetes, you will be able to measure your blood glucose levels at home. For more information, see the medical test Home Blood Glucose Test.
• A glycohemoglobin test can help monitor the long-term control of blood glucose levels in people with diabetes. This test is the preferred method of monitoring long-term control of blood sugar levels. For more information, see the medical test Glycohemoglobin (GHb).
• An oral glucose tolerance test may be done with a blood glucose test to confirm a diagnosis of diabetes. An oral glucose tolerance test is most commonly done to screen pregnant women for gestational diabetes. For more information, see the medical test Oral Glucose Tolerance Test.

Magnesium

Magnesium is a mineral that’s crucial to the body’s function. Magnesium helps keep blood pressure normal, bones strong, and the heart rhythm steady.

Magnesium Uses

Experts say that many people in the U.S. aren’t eating enough foods with magnesium. This mild magnesium deficiency could put them at risk for a number of diseases.

For instance, there’s good evidence that eating foods high in magnesium and other minerals can lower blood pressure. Magnesium supplements may help some people with heart disease and osteoporosis. Type 2 diabetes is also associated with low magnesium.

Intravenous or injected magnesium is used to treat other conditions, such as eclampsia during pregnancy and severe asthma attacks. Magnesium is also the main ingredient in many antacids and laxatives. Ask your doctor about other uses of magnesium.

Severe magnesium deficiencies are rare. They’re more likely in people who

• Have kidney disease
• Have Crohn’s disease or other conditions that affect digestion
• Have parathyroid problems
• Take antibiotics or drugs for diabetes and cancer
• Are older adults
•  Abuse alcohol  

Doctors sometimes suggest that people with these conditions take magnesium supplements.

Magnesium Dose & Instructions for Use

 

The recommended dietary allowance (RDA) includes the magnesium you get from both the food you eat and any supplements you take.

Category	Recommended Dietary Allowance (RDA)
CHILDREN
1-3 years	80 mg/day
4-8 years	130 mg/day
9-13 years	240 mg/day
FEMALES
14-18 years	360 mg/day
19-30 years	310 mg/day
31 years and over	320 mg/day
Pregnant	Under 19 years: 400 mg/day 19 to 30 years: 350 mg/day 31 years and up: 360 mg/day
Breastfeeding	Under 19 years: 360 mg/day 19 to 30 years: 310 mg/day 31 years and up: 320 mg/day
MALES
14-18 years	410 mg/day
19-30 years	400 mg/day
31 years and up	420 mg/day

 

It’s safe to get high levels of magnesium from food. But excessive use of magnesium supplements can be toxic. The upper limit — the highest dose a person can take — of magnesium supplements is

• 65 mg/day for children ages 1-3
• 110 mg/day for children ages 4-8
• 350 mg/day for adults and children ages 9 and up.

Magnesium Food Sources

Natural food sources of magnesium include:

• Green, leafy vegetables, like spinach
• Nuts
• Beans, peas, and soybeans
• Whole-grain cereals

Whole foods are always best. Magnesium can be lost during refinement and processing.

Magnesium Supplement Information

Magnesium comes in many forms. Magnesium is in multivitamins, antacids, and laxatives. Doctors also give magnesium intravenously or by injection. Like any supplement, keep magnesium in a cool, dry place, away from humidity and direct sunlight.

Magnesium Warnings

• Side effects. Magnesium supplements can cause nausea, cramps, and diarrhea.
• Interactions. Magnesium supplements may not be safe for people who take diuretics, heart medicines, or antibiotics.
• Risks. People with diabetes or intestinal disease shouldn’t take magnesium without checking with a doctor.
• Overdose. Signs of a magnesium overdose include nausea, diarrhea, low blood pressure, muscle weakness, and fatigue. At very high doses, it can be fatal.