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.
Galactosemia Tests
A galactosemia test is a blood test given to newborns to check for a rare genetic metabolic disorder called galactosemia. Metabolic disorders affect metabolism, the process your body uses to make energy from the food you eat. Galactosemia can be inherited (passed down through families), but to have the condition, your baby has to receive the gene from both parents. 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.
G6PD Test
This test measures the amount of G6PD in your blood. G6PD stands for glucose-6-phosphate dehydrogenase. It's an enzyme, a protein that speeds up certain chemical reactions in your body. It helps your red blood cells work properly. Red blood cells move oxygen from your lungs to every cell in your body. Your cells need oxygen to grow, reproduce, and stay healthy.
Fungal Culture Test
A fungal culture test helps diagnose fungal infections . Fungal infections may happen if you are exposed to fungi (more than one fungus). Fungi are plant-like life forms, such as yeasts and molds . Fungi live everywhere:
Free Light Chains
A free light chains test measures the level of free light chains in your blood. Light chains are proteins made by plasma cells, a type of white blood cell. Light chains usually link up with other proteins called heavy chains. Together, the light and heavy chains make immunoglobulins, also called antibodies. Antibodies are proteins that your immune system makes to fight germs such as viruses and bacteria .
Follicle-Stimulating Hormone (FSH) Levels Test
This test measures the level of follicle-stimulating hormone (FSH) in a sample of your blood. A hormone is a chemical messenger in your bloodstream that controls the actions of certain cells or organs. FSH plays an important role in sexual development in children and fertility in adults.
Flu (Influenza) Test
Flu is short for influenza. It is a respiratory infection caused by viruses . Respiratory infections may affect your nose, throat, and/or lungs. Most flu tests check a sample of fluid from your nose or throat to find out if you're infected with a flu virus.
Ferritin Blood Test
A ferritin blood test measures the level of ferritin in your blood. Ferritin is a protein that binds to iron and stores it in your body. You need iron to make healthy red blood cells. Red blood cells carry oxygen from your lungs to the rest of your body. Iron is also important for healthy muscles, bone marrow, and organs, including brain development in children.
Fasting for a Blood Test
If your health care provider has told you to fast before a blood test, it means you should not eat or drink anything, except plain water, for several hours before your test. While you're fasting for a blood test, you should also not :
Estrogen Levels Test
An estrogen test measures the level of estrogens in a sample of your blood, urine (pee), or saliva (spit).
Estimated Glomerular Filtration Rate (eGFR) and GFR Tests
Estimated glomerular filtration rate (eGFR) and GFR tests check how well your kidneys are working. Your kidneys are two organs on either side of your spine just below your rib cage. They have tiny filters called glomeruli. These filters remove waste and extra water from your blood and get rid of them through your urine (pee).
Erythrocyte Sedimentation Rate (ESR)
Erythrocytes are red blood cells. The sedimentation rate is the time it takes for your red blood cells to settle at the bottom of a test tube. An erythrocyte sedimentation rate (ESR) is a blood test that can show if you have inflammation in your body. Inflammation is your immune system's response to injury, infection, and many other conditions, including immune system disorders , certain cancers , and blood disorders .
Epithelial Cells in Urine
Epithelial cells cover the inside and outside of the surfaces of your body. They are found on your skin, blood vessels, and organs, including your urinary tract (which includes your kidneys, ureters, bladder, and urethra).
Electrolyte Panel
Electrolytes are minerals that have an electrical charge when they are dissolved in water or body fluids. You have electrolytes in your blood, urine, tissues, and other body fluids. They are important because they help:
Drug Testing
Drugs are chemical substances that can change how your body and mind work. A drug test looks for signs of illegal drugs or certain prescription and/or over-the-counter (OTC) medicines that can be misused. The test is usually done with a sample of your urine (pee). Less commonly, drug testing uses a sample of your blood, saliva (spit), hair, sweat, fingernails, or breath. The purpose of a drug test is to look for drug use and misuse, which includes:
Diabetes Tests
Diabetes , also known as diabetes mellitus, is a disease that affects how your body uses glucose ( blood sugar ). Glucose is your body's main source of energy. A hormone (a chemical messenger in your bloodstream that controls the actions of certain cells or organs) called insulin helps move glucose from your bloodstream into your cells.
DHEA Sulfate Test
This test measures the levels of DHEA sulfate (DHEAS) in your blood. DHEAS stands for dehydroepiandrosterone sulfate. DHEAS is mostly made in the adrenal glands, two small glands located above your kidneys. Your adrenal glands help control your heart rate, blood pressure, and other body functions. They make different types of hormones you need to stay healthy. This includes cortisol, a hormone that helps with your immune system , and DHEAS, a steroid hormone.
Dengue Fever Test
Dengue fever is a viral infection spread to people through bites from infected mosquitoes . A dengue fever test checks a sample of your blood to see if you have the virus.
Cytomegalovirus (CMV) Tests
Cytomegalovirus (CMV) tests check for signs of CMV in your blood, sputum, or other body fluids. CMV is a virus in the herpes family. Other types of herpes viruses include the viruses that cause chickenpox and mononucleosis (mono) .
CSF Immunoglobulin G (IgG) Index
CSF stands for cerebrospinal fluid. IgG stands for immunoglobulin G. It is a type of antibody. Antibodies are proteins that your immune system makes to fight germs . A CSF IgG index measures the levels of IgG in your cerebrospinal fluid.
Crystals in Urine
A crystals in urine test checks a sample of your urine (pee) under a microscope to look for crystals. The test shows what the crystals are made of, how large they are, and how many are in your urine.
Creatinine Test
This test measures creatinine levels in a sample of your blood and/or urine (pee). Creatinine is a normal waste product in your body. It's made when you use your muscles and some of the muscle tissue breaks down.
Creatine Kinase
This test measures the amount of creatine kinase (CK) in a sample of your blood. CK is also called creatine phosphokinase (CPK).
Cortisol Test
A cortisol test measures the level of cortisol in your blood, urine (pee), or saliva (spit). Cortisol is a hormone made by your adrenal glands, two small glands that sit above your kidneys. Hormones are chemical messengers in your bloodstream that control the actions of certain cells or organs. Cortisol affects almost every organ and tissue in your body. It helps your body:
Cord Blood Testing and Banking
Cord blood is the blood left in the umbilical cord after a baby is born. The umbilical cord connects a mother to her unborn baby during pregnancy . It contains blood vessels that bring nourishment to the baby and remove waste products.