Testing Knowledge
Test Directory
Source-backed test guides: what each test is for, how it is performed, its limitations, and which reviewed products serve it. Personal health questions are answered with knowledge and preparation guidance — not supplier sales.
BRAF Genetic Test
A BRAF genetic test uses a sample of tumor tissue, bone marrow, or blood to look for changes in a gene called BRAF . Changes in your genes are also called gene variants or mutations. The test is usually done to look for changes in the BRAF gene that may be involved in cancer .
Bone Marrow Tests
Bone marrow is a soft, spongy tissue found in the center of your bones. Bone marrow makes different types of blood cells, including:
Blood Smear
A blood smear is a test that's used to help diagnose and monitor a wide variety of blood disorders and other conditions that affect your blood. The test checks a sample of your blood under a microscope to see whether your blood cells look normal. It looks at your:
Blood in Urine
A urinalysis, which includes a test for blood in urine, is used to check your general health, including the health of your urinary tract, kidneys, and liver. The test can also be used to check for other health problems besides blood in urine.
Blood Glucose Test
A blood glucose test measures the glucose levels in your blood. Glucose is a type of sugar. It is your body's main source of energy. It comes from the food you eat. A hormone called insulin helps move glucose from your bloodstream into your cells for use as energy. If you have too much or too little glucose in your blood, it may be a sign of a serious medical condition.
Blood Differential
A blood differential test measures the amount of each type of white blood cell (WBC) that you have in your blood. This test can help diagnose or monitor an infection or condition that affects your immune system .
Blood Alcohol Level
A blood alcohol test measures the amount of alcohol (also called ethanol) in a sample of your blood. Alcohol is the ingredient in beer, wine, and distilled spirits (liquor) that makes you feel intoxicated (drunk).
Bilirubin in Urine
A bilirubin in urine test measures the levels of bilirubin in your urine. Normally, bilirubin isn't found in urine. If there is bilirubin in your urine (called bilirubinuria), it may be an early sign of a liver condition .
Bilirubin Blood Test
A bilirubin blood test measures the levels of bilirubin in your blood. Bilirubin is a yellowish substance made during your body's normal process of breaking down old red blood cells. Bilirubin is found in bile, a fluid your liver makes to help you digest food.
Beta 2 Microglobulin (B2M) Tumor Marker Test
A beta-2 microglobulin tumor marker test measures the amount of a protein called beta-2 microglobulin (B2M) in your body fluids. The test usually uses a sample of your blood. It may also be done using urine (pee) or in rare cases cerebrospinal fluid (CSF).
BCR-ABL1 Genetic Test
A BCR-ABL1 genetic test uses a sample of blood or bone marrow to look for an abnormal gene called BCR-ABL1. This abnormal gene is found in certain types of blood cancer , such as chronic myeloid leukemia (CML).
Basic Metabolic Panel (BMP)
A basic metabolic panel (BMP) measures eight different substances in your blood. It provides important information about your body's fluid balance , your metabolism (the process your body uses to make energy from food you eat), and how well your kidneys are working. This test is often used to check your general health.
Bacteria Culture Test
A bacteria culture test can determine if you have a bacterial infection and, if so, which type of bacteria is causing it. To do a bacterial culture test, you will need to give a sample of your blood, urine, skin, or other tissue. The type of sample depends on where the infection is located.
Autoantibody Testing
Autoantibody testing checks a sample of your blood for autoantibodies, proteins made by the immune system .
AST Test
An AST blood test measures the amount of AST in your blood. This test is commonly used to help diagnose liver damage or disease .
Arterial Blood Gas (ABG) Test
An arterial blood gas (ABG) test measures the amount of oxygen and carbon dioxide (CO2) in a sample of your blood. The blood oxygen measurement shows how well your lungs move oxygen from the air into your blood when you breathe in. The carbon dioxide measurement shows how well your lungs remove carbon dioxide from your blood when you breathe out.
Antineutrophil Cytoplasmic Antibodies (ANCA) Test
An ANCA test looks for antineutrophil cytoplasmic antibodies (ANCA) in a sample of your blood. Antibodies are proteins that your immune system makes to fight foreign substances, such as viruses and bacteria. ANCAs, however, are autoantibodies, which are antibodies that attack your own healthy tissues and organs by mistake. This can lead to the development of an autoimmune disease .
Antibody Serology Tests
Antibody serology tests look for specific antibodies in your blood. Antibodies are proteins your immune system makes to fight disease-causing germs (also called pathogens), such as viruses and bacteria .
Anti-Müllerian Hormone Test
An anti-müllerian hormone (AMH) test measures the amount of AMH in a blood sample. In males, the testicles (or testes), which are glands that make sperm and hormones, make AMH. In females, the ovaries, which are glands that store and develop eggs and make hormones, make AMH.
Anion Gap Blood Test
An anion gap blood test gives a measurement of the acid-base balance (pH balance) in your blood. This lets you know whether your blood is too acidic or not acidic enough. The test also checks for an electrolyte imbalance in your blood. To do the measurement, an anion gap test uses the results of an electrolyte panel or other blood tests that measure your electrolytes.
ANA (Antinuclear Antibody) Test
An ANA test is a blood test that looks for antinuclear antibodies in your blood. Antibodies are proteins that your immune system makes to fight foreign substances, like viruses and bacteria. But an antinuclear antibody attacks your healthy cells instead. It's called "antinuclear" because it targets the nucleus of the cells, which is in charge of sending signals that are needed for important cell functions.
Amylase Test
An amylase test measures the amount of amylase in your blood or urine (pee). Amylase is an enzyme, a protein that speeds up chemical reactions in your body. Amylase helps you digest carbohydrates . Most of the amylase in your body is made by your pancreas and salivary (spit) glands.
Ammonia Levels
An ammonia levels test measures the amount of ammonia in a sample of your blood. Ammonia is also called NH3. It is a normal waste product in your body. Healthy bacteria in your intestines make ammonia when you digest protein in the foods you eat.
ALT Blood Test
An ALT test measures the amount of ALT in your blood. This test is commonly used to help diagnose liver damage or disease .