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.
Alpha-Fetoprotein (AFP) Test
An AFP test is a blood test that measures the level of alpha-fetoprotein (AFP) in your blood when you are pregnant. The test checks your baby's risk of having certain birth defects and genetic problems , but it does not diagnose any health conditions. The test is usually done between 15 and 20 weeks of pregnancy .
Alpha-1 Antitrypsin Testing
Alpha-1 antitrypsin (AAT) testing uses a sample of blood or a cheek swab to diagnose a condition called alpha-1 antitrypsin deficiency (AAT deficiency). This condition is sometimes known as "alpha-." or AATD. If you have AAT deficiency, your body doesn't make enough AAT.
Alpha Fetoprotein (AFP) Tumor Marker Test
An AFP tumor marker test is a blood test that measures the level of AFP (alpha-fetoprotein) in a sample of your blood. AFP is a protein that the liver makes when its cells are growing and dividing to make new cells. AFP levels are normally high in a fetus, but after birth, they drop very low. Healthy children and adults who aren’t pregnant have very little AFP in their blood.
Allergy Blood Test
An allergy blood test measures the amount of allergy-causing antibodies called immunoglobulin E (IgE). Antibodies are proteins that your immune system makes to fight foreign substances, such as viruses and bacteria . But your immune system may also make them in response to allergens. These are harmless substances, such as pollen and peanuts, that may cause an allergic reaction in some people.
Alkaline Phosphatase
An alkaline phosphatase (ALP) test measures the amount of ALP in your blood. ALP is an enzyme, a protein that speeds up certain chemical reactions in your body. ALP is found in all your body tissues, but higher amounts can be found in your liver, bile ducts, and bones. Each part of your body makes a different type of ALP.
Aldosterone Test
An aldosterone test measures the amount of aldosterone (ALD) in your blood or urine (pee). ALD is a hormone made by your adrenal glands, two small glands that sit above your kidneys. ALD helps keep your blood pressure stable by helping to balance the levels of two electrolytes in your blood, sodium and potassium .
Albumin Blood Test
An albumin blood test measures the amount of albumin in your blood. Albumin is a protein made by your liver. Low albumin levels can be a sign of liver or kidney disease or another medical condition. High levels may be a sign of dehydration .
Adrenocorticotropic Hormone (ACTH)
This test measures the level of adrenocorticotropic hormone (ACTH) in a sample of your blood. A hormone is a chemical messenger in your bloodstream that controls the actions of certain cells or organs. ACTH tells your adrenal glands, two small glands that sit above your kidneys, to make another hormone called cortisol.
Acetaminophen Level
This test measures the amount of acetaminophen in your blood. Acetaminophen is a medicine used in many over-the-counter (OTC) and prescription medicines. It is used to relieve pain and reduce fever . It comes in liquid, chewable, capsule, or pill form. It is found in many brand name medicines, including Tylenol and Excedrin. Outside the U.S., it's called paracetamol. Acetaminophen can also be combined with other active ingredients in medicines that treat allergy, cough, colds, flu, and sleeplessness.
Newborn Screening Panel (Inborn Errors of Metabolism)
Population screening of newborns from dried blood spots for treatable inborn errors of metabolism before symptoms appear.
Helicobacter pylori Stool Antigen
A non-invasive stool test for active H. pylori infection, suitable for both diagnosis and verification of eradication.
Fecal Immunochemical Test (FIT)
A stool test detecting hidden blood from the lower bowel; the main screening entry point for colorectal cancer programmes.
Human Chorionic Gonadotropin (hCG, Pregnancy Test)
The hormone detected by pregnancy tests; also used in medicine to assess certain pregnancies and tumours.
Blood Gas and Electrolytes (ABG)
Point-of-care measurement of oxygenation, ventilation, acid-base status, and electrolytes in critically ill patients.
Prostate-Specific Antigen (PSA)
A protein produced by prostate tissue; elevated values can reflect prostate cancer but also common benign conditions.
25-OH Vitamin D
The main circulating form of vitamin D and the standard measure of vitamin D status.
Ferritin
The intracellular iron-storage protein measurable in serum; the most useful single test of iron stores.
Procalcitonin (PCT)
A biomarker that rises markedly in systemic bacterial infection; used to support antibiotic decisions in respiratory infections and sepsis pathways.
C-Reactive Protein (CRP / hs-CRP)
An acute-phase protein that rises rapidly during inflammation; used to detect and monitor infection and inflammatory disease.
Thyroid Stimulating Hormone (TSH)
The pituitary hormone that regulates the thyroid; the primary first-line test for thyroid dysfunction.
Glycated Hemoglobin (HbA1c)
A long-term measure of average blood glucose over roughly the preceding two to three months, used to diagnose and monitor diabetes.
Activated Partial Thromboplastin Time (APTT)
A clotting test of the intrinsic and common pathways, used to monitor unfractionated heparin and investigate prolonged bleeding histories.
Prothrombin Time / INR (PT/INR)
A clotting test measuring the extrinsic pathway, standardised internationally as INR to monitor vitamin K antagonist therapy and assess bleeding risk.
D-Dimer
A fibrin degradation product used mainly to help rule out venous thromboembolism when clinical probability is low.