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.
Comprehensive Metabolic Panel (CMP)
A comprehensive metabolic panel (CMP) is a routine blood test that measures 14 different substances in a sample of your blood. It provides important information about your metabolism (how your body uses food and energy) and the balance of certain chemicals in your body.
Complete Blood Count (CBC)
A complete blood count, or CBC, is a group of blood tests that measure the number and size of the different cells in your blood. A CBC measures:
Complement Blood Test
A complement blood test measures the levels and/or activity of a group of proteins that are part of the complement system. This system "complements" or enhances your body's defenses against infections and other diseases. Your immune system makes antibodies, which are proteins to fight disease-causing substances like viruses and bacteria. The proteins in the complement system will also help fight the infection or disease. These proteins work together in a sequence, with one protein activating the next.
Coagulation Factor Tests
Coagulation factors are proteins in your blood. They help form blood clots to stop bleeding when you have an injury. These proteins are also called clotting factors. You have several different types of clotting factors that are all important for making blood clots.
Chymotrypsin in Stool
This test measures the amount of chymotrypsin in a stool (poop) sample. Chymotrypsin is an enzyme, a protein that speeds up certain chemical reactions in your body. It is released by your pancreas (an organ behind your stomach) to help break down the protein in your food during digestion. If your pancreas is working as it should, there will be some chymotrypsin in your stool sample.
Cholesterol Levels
A cholesterol test is a blood test that measures the amount of cholesterol and triglycerides (a type of fat) in your blood. Cholesterol is a waxy, fat-like substance that's found in your blood and every cell of your body. Your body needs some cholesterol to make hormones , vitamin D , and substances that help you digest foods.
Chloride Blood Test
A chloride blood test measures the amount of chloride in your blood. Chloride is a type of electrolyte. Electrolytes are electrically charged minerals that help control the amount of fluids and the balance of acids and bases (pH balance) in your body. You have electrolytes in your blood, urine, tissues, and other body fluids.
Ceruloplasmin Test
A ceruloplasmin test measures the amount of ceruloplasmin in a sample of your blood. Your liver makes ceruloplasmin by attaching copper to a protein. Your liver releases the ceruloplasmin into your bloodstream so it can carry copper to the parts of your body that need it.
Cerebrospinal Fluid (CSF) Analysis
A cerebrospinal fluid (CSF) analysis tests a sample of your CSF for diseases that affect the brain and spinal cord, which make up your central nervous system. Your central nervous system controls and coordinates everything you do, including your ability to move, breathe, see, think, and more.
Celiac Disease Screening
A celiac disease screening is a blood test that looks for signs that you may have celiac disease , an autoimmune disorder that causes a serious allergic reaction to gluten. Gluten is a protein found in wheat, barley, rye and other grains. It may also be found in other products like vitamins and supplements , hair and skin products, toothpaste, and lip balm.
CD4 Lymphocyte Count
A CD4 count is a blood test that measures the number of CD4 cells in a sample of your blood. CD4 cells are a type of white blood cell that circulates throughout the body in the blood. They're also called CD4 T lymphocytes or "helper T cells." That's because they help fight infection by triggering your immune system to destroy viruses, bacteria, and other germs that may make you sick.
CCP Antibody Test
This test looks for CCP (cyclic citrullinated peptide) antibodies in your blood. CCP antibodies, also called anti-CCP antibodies, are a type of antibody called autoantibodies. Antibodies and autoantibodies are proteins made by the immune system :
Carbon Dioxide (CO2) in Blood
A carbon dioxide (CO2) blood test measures the amount of carbon dioxide in your blood. Carbon dioxide is an odorless, colorless gas. It is a waste product from metabolism, the process your body uses to make energy from food you eat.
Calprotectin Stool Test
A calprotectin stool test measures a protein called calprotectin in a sample of your stool (poop). The test is also called a fecal calprotectin test. It's used to check for inflammation (swelling and irritation) in your intestines.
Calcium in Urine Test
A calcium in urine test measures the amount of calcium in your urine (pee). If your urine calcium levels aren't normal, it may be a sign of kidney disease , a parathyroid disorder , bone diseas e, or another condition that affects how your body uses calcium.
Calcium Blood Test
A calcium blood test measures the amount of calcium in your blood. Too much or too little calcium in your blood may be a sign of a wide range of medical conditions, such as bone disease , thyroid diseas e, parathyroid disorders , kidney disease , and other conditions.
Calcitonin Test
A calcitonin test uses a sample of your blood to measure your levels of calcitonin, a hormone made in your thyroid gland by cells called “C cells.” Your thyroid is a small, butterfly-shaped gland in your neck, and C cells grow on the inside part of your thyroid (the medulla).
CA-125 Blood Test (Ovarian Cancer)
This test measures the amount of a protein called CA-125 (cancer antigen 125) in a sample of your blood. CA-125 is a type of tumor marker. Tumor markers are substances that are often made by cancer cells or by normal cells in response to cancer.
CA 19-9 Blood Test (Pancreatic Cancer)
A CA 19-9 test measures the amount of a protein called CA 19-9 (cancer antigen 19-9) in a sample of your blood. CA 19-9 is a type of tumor marker. Tumor markers are substances made by cancer cells or by normal cells in response to cancer .
C. diff Testing
C. diff testing checks a sample of your stool (poop) for signs of an infection with a bacteria called C. diff . C. diff is also called C. difficile or Clostridioides difficile . It used to be called Clostridium difficile .
C-Reactive Protein (CRP) Test
A c-reactive protein test measures the level of c-reactive protein (CRP) in a sample of your blood. Your liver makes CRP in response to inflammation.
C-Peptide Test
This test measures the level of C-peptide in a sample of your blood or urine (pee). C-peptide is a chain of amino acids (the building blocks of proteins) that your pancreas makes in the process of making insulin. Insulin is a hormone that your pancreas makes to help blood glucose (blood sugar) get into your cells, where it can be used for energy. This helps keep your blood glucose at healthy levels.
BUN (Blood Urea Nitrogen)
A BUN, or blood urea nitrogen test, measures the amount of urea nitrogen in your blood. Urea nitrogen is a waste product that forms as your body breaks down proteins. It's carried in your blood and then removed by your kidneys when you urinate (pee).
BRCA Genetic Test
BRCA is short for "breast cancer gene." A BRCA genetic test uses a sample of your blood, saliva (spit), or cells from inside of your cheek to look for changes in your BRCA1 and BRCA2 genes. Genes are parts of DNA in your cells that you inherit from your parents. You inherit two copies of each gene, one from each parent. Genes carry information that controls what you look like and how your body works.