A C-reactive protein (CRP) test is a blood test that measures the amount of a protein called C-reactive protein in your blood. C-reactive protein measures general levels of inflammation in your body. High levels of CRP are caused by infections and many long-term diseases. But a CRP test cannot show where the...

Creatinine and creatinine clearance tests measure the level of the waste product creatinine (say "kree-AT-uh-neen") in your blood and urine. These tests tell how well your kidneys are working. Another substance, creatine (say "KREE-uh-teen"), is...

This test measures the amount of lead in a person's blood. Lead is a poisonous (toxic) metal that can damage the brain and other parts of the body. A lead test may be done on blood taken from the vein, a finger (finger stick), or the heel (heel stick). A person can be exposed to lead: By eating or drinking...

Looks at various tests used to check how well the thyroid gland is working. Covers what results might mean. Also looks at what might affect a test. Offers links to info on other tests that might be useful, including thyroid-stimulating hormone (TSH) test.

The blood uric acid test measures the amount of uric acid in a blood sample. Uric acid is produced from the natural breakdown of your body's cells and from the foods you eat. Most of the uric acid is filtered out by the kidneys and passes out of the body in urine. A small amount passes out of the body in stool. But if...

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. But if the pancreas or salivary glands become damaged or blocked, more amylase is usually released into the blood and urine. In the...

Myoglobin is a protein found in heart tissue and other muscles. It is released into the blood after damage to the heart or other muscles. Damage can occur from a serious event such as a heart attack or a burn. Myoglobin can be checked with a blood test or a urine test.

It's important to take care of your supplies so that you can test your blood sugar safely and get the most accurate results. Take care of your meter. Follow the care instructions from the manufacturer. Some meters need to be cleaned regularly and have their batteries changed now and then. Meters can be damaged if...

An aldosterone test measures the level of aldosterone (a hormone made by the adrenal glands), in the blood. Aldosterone helps regulate sodium and potassium levels in the body. This helps control blood pressure and the balance of fluids and electrolytes in the blood. The kidney hormone renin normally stimulates the...

Doctors follow guidelines from experts to decide when to test adults for type 2 diabetes. Talk with your doctor about your risk for type 2 diabetes and how often you need to be tested. Testing involves a blood test that is simple and usually very...

The D-xylose absorption test measures the level of D-xylose, a type of sugar, in a blood or urine sample. This test is done to help diagnose problems that prevent the small intestine from absorbing nutrients in food. D-xylose is normally easily...

The guaiac fecal occult blood test (gFOBT) is used to screen for colorectal cancer. Cancer in the colon or polyps in the colon are more likely to bleed than normal colon tissue is. This test uses a chemical to check for very small amounts of blood in the stool. If signs of blood are found in the stool sample, more...

The sedimentation rate (sed rate) blood test measures how quickly red blood cells (erythrocytes) settle in a test tube in one hour. The more red cells that fall to the bottom of the test tube in one hour, the higher the sed rate. When inflammation is present in the body, certain proteins cause red blood cells to stick...

Briefly discusses basic metabolic panel, a blood test that measures your sugar (glucose) level, electrolyte and fluid balance, and kidney function. Provides links to more info on specific tests such as blood urea nitrogen, creatinine, and potassium tests.

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...

A sodium test checks how much sodium is in the blood. Sodium is both an electrolyte and mineral. It helps keep the water (the amount of fluid inside and outside the body's cells) and electrolyte balance of the body. Sodium is also important in how nerves and muscles work. Most of the sodium in the body is found in blood...

During the first trimester of pregnancy, screening tests for birth defects may be done. These tests look for possible problems with your baby. The tests may be called first-trimester screening, combined first-trimester screening, or the combined screening. The screening tests show the chance of your baby having certain...

Hemochromatosis gene (HFE) testing is a blood test used to check for hereditary hemochromatosis, an inherited disorder that causes the body to absorb too much iron. The iron then builds up in the blood, liver, heart, pancreas, joints, skin, and other organs. In its early stages, hemochromatosis can cause joint and belly...

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 color. Bilirubin circulates in the...

Lab tests play an important role in your health care. They help your doctor make a diagnosis or treatment decisions. But they may not provide all of the information that your doctor needs. Your doctor will not usually make a decision or diagnosis based only on the results of a lab test, unless the test results are...

A carbon monoxide blood test is used to detect carbon monoxide poisoning. Poisoning can happen if you breathe air that contains too much carbon monoxide (CO). This gas has no color, odor, or taste, so you can't tell when you are breathing it. The test measures the amount of hemoglobin in your blood that has bonded with...

Has links on complete blood count, sedimentation rate tests, and anemia. Also includes links to lymph topics such as swollen glands/other lumps under the skin and lymphedema.

A toxicology test ("tox screen") checks for drugs or other chemicals in your blood, urine, or saliva. Drugs can be swallowed, inhaled, injected, or absorbed through the skin or a mucous membrane. In rare cases, a tox screen may check your stomach contents or sweat. A tox screen may check for one certain drug or for up...

A luteinizing hormone test measures the amount of luteinizing hormone (LH) in a sample of blood or urine. LH is produced by the pituitary gland. LH helps regulate the menstrual cycle and egg production ( ovulation). LH levels normally change with the phase of the menstrual cycle. This hormone goes up fast just before...