A rubella blood test detects antibodies that are made by the immune system to help kill the rubella virus. These antibodies remain in the bloodstream for years. The presence of certain antibodies means a recent infection, a past infection, or that you have been vaccinated against the disease. Rubella (also called German...

Vision is the result of electrical signals that travel between the retina and the part of the brain involved with vision (occipital cortex). Electrophysiology tests check to see how well this visual nerve pathway sends the electrical signals needed for vision. These tests measure electrical activity that occurs in your...

A rheumatoid factor (RF) blood test measures the amount of the RF antibody present in the blood. Normally, antibodies are produced by the immune system to help destroy and get rid of invading bacteria and viruses that can cause disease. But the RF antibody can attach to normal body tissue and cause damage. A high level...

An aldosterone test measures the level of aldosterone (a hormone made by the adrenal glands) in the urine. 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...

A cortisol test measures the level of the hormone cortisol in a 24-hour sample of urine. The cortisol level may show problems with the adrenal glands or the pituitary gland. Cortisol is made by the adrenal glands. Cortisol levels get higher when the pituitary gland releases adrenocorticotropic hormone (ACTH). Cortisol...

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...

An alkaline phosphatase (ALP) test measures the amount of the enzyme 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 during pregnancy. The liver makes more ALP than the other organs or the bones. Some conditions cause large...

A ferritin blood test checks the amount of ferritin in the blood. Ferritin is a protein in the body that binds to iron; most of the iron stored in the body is bound to ferritin. Ferritin is found in the liver, spleen, skeletal muscles, and bone marrow. Only a small amount of ferritin is found in the blood. The amount of...

An estrogen test measures the level of the most important estrogen hormones in a blood or urine sample. It measures estradiol, estriol, and estrone. Estradiol is the most common type of estrogen measured for nonpregnant women. The amount of estradiol in a woman's blood varies throughout her menstrual cycle. After...

A cold agglutinins blood test is done to check for conditions that cause the body to make certain types of antibodies called cold agglutinins. Cold agglutinins are normally made by the immune system in response to infection. They cause red blood cells to clump together (agglutinate) at low temperatures. Healthy people...

Anoscopy, proctoscopy, and sigmoidoscopy tests allow your doctor to look at the inner lining of your anus, your rectum, and the lower part of the large intestine (colon). These tests are used to look for abnormal growths (such as tumors or polyps), inflammation, bleeding, hemorrhoids, and other conditions (such as...

Provides links that give tips, like making the most of your appointment and getting better care at lower costs. Also includes links on understanding lab results and deciding whether to get a flu vaccine.

Outpatient services are medical procedures, surgeries, therapies, classes, or tests that are done in a qualified medical center without the need for an overnight stay. In general, outpatient centers focus on services for wellness and prevention, diagnosis, treatment, and rehabilitation. In these centers, a person may...

Describes pancreatic cancer. Talks about symptoms and what tests are used to diagnose it. Provides treatment details. Lists factors that raise your risk.

Describes various sleep studies used to diagnose sleep disorders. Discusses problems like snoring, sleep apnea, insomnia, and narcolepsy. Covers common sleep studies, including polysomnograms, multiple sleep latency tests, and the maintenance of wakefulness test.

At each prenatal visit during your first trimester, you'll be weighed and have your blood pressure checked. Your urine may also be checked for bacteria, protein, or sugar. As early as weeks 10 to 12, you may be able to hear your baby's heartbeat using a Doppler ultrasound. By the 20th week, the heart tone is strong...

Clopidogrel (Plavix) is a medicine to prevent blood clots, which can cause heart attacks and strokes. It may be prescribed after a heart attack, after angioplasty, and for people who have coronary artery disease or peripheral arterial disease. Some people have changes, or mutations, to a certain gene (CYP2C19). These...

A skin or wound culture is a test to find germs (such as bacteria, a virus, or a fungus ) that can cause an infection. A sample of skin, tissue, or fluid is added to a substance that promotes the growth of germs. If no germs grow, the culture is negative. If germs that can cause an infection grow, the culture is...

A comprehensive metabolic panel is a blood test that measures your sugar (glucose) level, electrolyte and fluid balance, kidney function, and liver function. Glucose is a type of sugar your body uses for energy. Electrolytes keep your body's fluids in balance. They also help keep your body working normally, including...

A chemistry screen is a blood test that measures the levels of several substances in the blood (such as electrolytes). A chemistry screen tells your doctor about your general health, helps look for certain problems, and finds out whether treatment for a specific problem is working. Some chemistry screens look at more...

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.

There is no medical test that can diagnose PTSD. Your doctor will ask you about your symptoms, how long you've had them, and how much they affect your daily activities. Your doctor may also ask about: The event or events that led to your symptoms. Traumatic events in your past, including those from childhood. Whether...

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...

Catecholamines (say "kat-uh-KOH-luh-meens") are hormones made mostly by your adrenal glands as a reaction to stress. When you feel stressed, these hormones increase heart rate, blood pressure, breathing rate, muscle strength, and mental alertness. They also lower the amount of blood that goes to the skin and intestines...