Discusses blood test used to check for thyroid gland problems. Explains how TSH causes thyroid gland to make hormones that help control metabolism. Covers how it is done and test results.

A complete blood count (CBC) gives important information about the kinds and numbers of cells in the blood, especially red blood cells, white blood cells, and platelets. A CBC helps your doctor check any symptoms that you may have, such as weakness, fatigue, or bruising. A CBC also helps him or her diagnose conditions...

Warfarin is a pill that you take regularly to help prevent blood clots or to keep a clot from getting bigger. Coumadin is the common brand name for warfarin. To make sure that warfarin is effectively thinning your blood, it's important to eat about the same amount of vitamin K every day. Here's why: Vitamin K normally...

This test for Tay-Sachs disease measures the amount of an enzyme called hexosaminidase A (Hex A) in the blood. Hex A breaks down fatty substances in the brain and nerves. Tay-Sachs is an inherited disease in which the body can't break down fatty substances as it should, so the fatty substances collect in the nerve cells...

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...

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...

Hepatitis C virus (HCV) test is a blood test that looks for the genetic material ( RNA) of the virus that causes hepatitis or for the proteins ( antibodies) the body makes against HCV. These proteins will be present in your blood if you have a hepatitis C infection now or have had one in the past. Different tests are...

Discusses oral glucose tolerance test that measures glucose (blood sugar) levels. Explains that test checks for gestational diabetes, prediabetes, and diabetes. Covers the types of tests done and how to prepare for them.

Discusses a test that checks urine for a protein called albumin. Covers possible kidney damage and diabetes. Explains how test is done. Discusses normal and abnormal values from the test. Covers what affects the test.

Carbon dioxide (CO2) is a gaseous waste product from metabolism. The blood carries carbon dioxide to your lungs, where it is exhaled. More than 90% of it in your blood exists in the form of bicarbonate (HCO3). The rest of it is either dissolved carbon dioxide gas (CO2) or carbonic acid (H2CO3). Your kidneys and lungs...

A viral load test measures how much HIV is in the blood. It's first measured when you're diagnosed with HIV. This serves as the baseline. Future measurements are compared with it. With treatment, the viral load should go down. Within a few months, there should be very little virus in your blood.

Discusses stool analysis, a test used to look for bacteria, parasites, or blood in the digestive tract. Covers why and how it is done. Looks at risks. Covers normal and abnormal results.

Discusses prostate-specific antigen (PSA) test to measure amount of PSA in the blood. Explains that test is often used for cancer screening or follow-up. Covers how test is done and how to prepare for it. Discusses what results mean.