Sperm penetration tests check to see if sperm can move through cervical mucus or join with (fertilize) an egg. These tests may be done when you're having trouble getting pregnant (infertility). There are different sperm penetration tests. The sperm mucus penetration test checks if sperm can move through the cervical...

Explains liver biopsy, also called percutaneous liver biopsy, a test used to look for liver diseases like hepatitis, cirrhosis, hemochromatosis, and cancer. Covers how to prepare and what to expect. Includes what results mean. Also lists risks.

Describes colonoscopy, a screening test that examines the lining of the large intestine. Explains that the test is done to look for polyps in the colon or rectum and to check for colorectal cancer. Discusses preparing for the test and how it is done.

Discusses blood glucose tests used to diagnose diabetes and prediabetes. Covers types of tests, including fasting blood sugar, 2-hour postprandial blood sugar, random blood sugar, and oral glucose tolerance. Discusses how to prepare and what results mean.

Paracentesis is a procedure to take out fluid that has collected in the belly ( peritoneal fluid) outside the intestines. This fluid buildup is called ascites. Ascites may be caused by infection, inflammation, an injury, or other conditions, such as cirrhosis or cancer. The fluid is taken out using a thin needle put...

Getting great care at a lower price is possible. Just like when you shop for food or clothes, there are things you can do to lower your health care costs. Save by taking charge of your health Here are some things you can do to take charge of your health and lower your health care costs. Protect your health with a...

A prolactin test measures the level of the hormone prolactin, which is made by the pituitary gland, in your blood. Pregnant women have high levels of prolactin, which helps make breast milk. During pregnancy, prolactin levels increase by 10 to 20 times. After the baby is born, prolactin stays high if you are...

A sweat test, also called a sweat chloride test, measures the amount of chloride in sweat. It is done to help diagnose cystic fibrosis. Normally, sweat on the skin surface contains very little chloride. People with cystic fibrosis have a high level of chloride in their sweat. During the sweat test, medicine that causes...

A spinal tap (also called a lumbar puncture) is a procedure to collect and look at the fluid ( cerebrospinal fluid, or CSF) that surrounds the brain and spinal cord. During a spinal tap, a needle is carefully inserted into the spinal canal low in the back (lumbar area). Samples of CSF are collected. The samples are...

Covers test done on a kidney stone to find out what the stone is made of. Links to info on types of stones, including calcium, uric acid, struvite, and cystine. Explains that test can help doctor decide treatment or give info on preventing more stones from forming.

Discusses blood test to check the different types of hemoglobin in the blood. Covers how some diseases, such as sickle cell disease, aplastic anemia, and leukemia, have abnormal types of hemoglobin. Discusses possible test results.

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 formed when food is changed into energy through a process called...

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...

Covers why and how parathyroid hormone tests are done. Covers what possible results might mean. Includes info on what might affect the test.

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...

Cardiac enzyme studies measure the levels of enzymes and proteins that are linked with injury of the heart muscle. The test checks for the proteins troponin I (TnI) and troponin T (TnT). If your heart muscle is injured, such as from a heart attack, troponin proteins leak out of damaged heart muscle cells, and their...

The carcinoembryonic antigen (CEA) test measures the amount of this protein that may appear in the blood of some people who have certain kinds of cancers, especially cancer of the large intestine ( colon and rectal cancer). It may also be present in people with cancer of the pancreas, breast, ovary, or lung. CEA is...

A gastrin test measures the level of the hormone gastrin in the blood. Gastrin is produced by cells, called G cells, in the stomach lining. When food enters the stomach, G cells trigger the release of gastrin in the blood. As blood levels of gastrin rise, the stomach releases acid (gastric acid) that helps break down...

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...

Doctors are experts on medical care. But you are the expert on yourself and your life. That's why it's important to be an active patient. When you're actively involved in decisions about your care, you can be sure that your choices reflect your values and beliefs. Here are some ways to become more active and involved in...

An adrenocorticotropic hormone test measures the level of adrenocorticotropic hormone (ACTH) in the blood to check for problems with the pituitary gland and adrenal glands. ACTH is made in the pituitary gland in response to the release of another hormone, called corticotropin-releasing hormone (CRH), by the...

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...

Discusses toxoplasmosis test, a blood test that checks pregnant women for antibodies to the Toxoplasma gondii parasite. Covers why and how it is done. Also discusses what results mean.

The overnight dexamethasone suppression test checks to see how taking a steroid medicine called dexamethasone changes the levels of the hormone cortisol in the blood. This test checks for a condition in which large amounts of cortisol are produced by the adrenal glands ( Cushing's syndrome). Normally, when the pituitary...

The serum protein electrophoresis (SPEP) test measures specific proteins in the blood to help identify some diseases. Proteins are substances made up of smaller building blocks called amino acids. Proteins carry a positive or a negative electrical charge, and they move in fluid when placed in an electrical field. Serum...