Build Your Own Blood Test

Alkaline phosphatase, usually shortened to ALP on a report, is an enzyme found in almost every tissue. Two sources account for nearly all of what reaches the blood. The first is the liver, and within it mainly the cells lining the small bile ducts. The second is bone, where the enzyme is released as new bone tissue is built. A raised result therefore does not yet say where the rise came from. That question is not answered by this one number. It is answered by the values beside it, by your age and by your situation.

Your ALT value shows how much alanine aminotransferase is in your blood. This enzyme sits mainly in the liver. That makes ALT the most liver-specific of the routine enzymes. When it reaches the blood, liver cells have been damaged. In adult men the reference range runs to 45 u/l, and in women to 34 u/l. A mildly raised result is common and has several causes. Fatty liver leads that list, well ahead of alcohol and hepatitis.

Your AST value shows how much aspartate aminotransferase is circulating in your blood. It is an enzyme that leaks out whenever cells are damaged. AST sits in the liver, but equally in skeletal muscle, heart muscle, kidneys, brain and red blood cells. That is why a raised AST is not, on its own, a liver value. A hard training session the day before explains the result more often than liver disease does. The reference range runs up to 35 u/l in men and 31 u/l in women. What the number means only becomes clear alongside ALT, gamma-GT and CK.

Albumin is the most abundant protein in the blood, produced by the liver. It maintains fluid balance, transports hormones and nutrients, and serves as an indicator of liver and kidney function.

Direct (conjugated) bilirubin is the water-soluble form of bilirubin that has been processed by the liver. Elevated levels may indicate bile duct obstruction or liver disease and are an important component of liver function assessment.

Total bilirubin measures the combined amount of direct and indirect bilirubin in your blood. Bilirubin is a waste product formed during the normal breakdown of red blood cells, and elevated levels may indicate liver disease, bile duct problems, or increased red blood cell destruction.

GGT (gamma-glutamyl transferase) is a liver and bile duct enzyme that serves as one of the most sensitive markers for hepatobiliary disorders. It is particularly responsive to alcohol consumption and may be elevated in bile duct obstruction, liver disease, and with certain medications.

Creatinine is a waste product that is continuously produced in your muscles. The kidneys filter it out of the blood and remove it in urine. The blood creatinine level is therefore a core number for kidney function. In Dutch it is written both as creatinine and as kreatinine. Because production depends on your muscle mass, the same figure reads differently per person. A raised creatinine does not automatically point to a kidney problem. This page explains what high and low values can mean. It also covers the everyday things that shift the result temporarily.

eGFR (estimated glomerular filtration rate) is a calculated measure of how effectively your kidneys filter waste from the blood. It is the gold standard for diagnosing and staging chronic kidney disease and is derived from blood creatinine or cystatin C levels along with demographic factors.

Free T3 (triiodothronine) is considered the most active thyroid hormone. It may play a key role in regulating metabolism, energy production, and body temperature. Healthcare providers often assess Free T3 alongside other thyroid markers for a comprehensive picture.

Free T4 (thyroxine) is the main hormone produced by the thyroid gland. It may serve as a precursor that your body converts into the more active T3. Healthcare providers often consider Free T4 a primary indicator of thyroid gland output.

TPO antibodies target the thyroid peroxidase enzyme involved in thyroid hormone production. Elevated levels may indicate autoimmune thyroid conditions such as Hashimoto's thyroiditis. Your healthcare provider can help determine what your TPO antibody results mean for your health.

TSH is thyroid-stimulating hormone. The pituitary gland makes it, and uses it to drive your thyroid. At the laboratory that runs the test the usual adult range runs from 0.27 to 4.20 mE/L. A high TSH usually fits an underactive thyroid. A low value usually fits an overactive one. That direction feels inverted, and it is. TSH is the pituitary signal, not the thyroid hormone itself. Laboratories use slightly different limits from one another. Always read the reference value printed on your own result. And a single measurement is never a diagnosis.