A blood test report can look like a page of abbreviations: ALT, MCV, eGFR, HbA1c. Each one is a marker, a single thing the laboratory measured. This glossary explains 30 of the most common blood test markers in one sentence each, grouped by the system they relate to, and names the test in the BPR catalogue where you will find them. It describes what a marker measures, not what your own result means: that conversation belongs with your doctor, who sees the whole picture.
How to read this glossary
Every marker on a report comes with a reference range, the band of values the laboratory expects in most people. A value slightly above or below it is common and often has an ordinary explanation. Thyroid specialists, for example, point out that results need to be read in context, because pregnancy, other illness and some medicines change them (Koulouri et al., 2013). Use the sentences below as a map, not as a verdict.
Blood count
These markers come from the Full Blood Count, which LML describes as measuring red blood cells, white blood cells and platelets.
- Haemoglobin: the substance inside red blood cells that carries oxygen around the body.
- Red cell count: the number of red blood cells in a given volume of blood.
- MCV (mean cell volume): the average size of the red blood cells; the NHS explains that a lack of vitamin B12 or folate makes the body produce abnormally large ones.
- White cell count: the number of white blood cells, which LML notes can help identify infections.
- Neutrophils and lymphocytes: two of the five types of white cell in the differential, which shows which kinds of white cell are present.
- Platelet count: the number of platelets, the third component the full blood count measures alongside red and white cells.
Iron
All four are in the Iron Status Profile, which LML says can be done on a finger-prick sample.
- Serum iron: how much iron is in your blood right now.
- Ferritin: a protein that stores iron, so it reflects the body's iron reserves.
- Transferrin saturation: another way of showing how well your blood is using the iron available.
- TIBC (total iron-binding capacity): the blood's capacity to bind and carry iron.
A review in The Lancet notes that inflammation can hold iron back from the blood, which is one reason iron markers are read together rather than one at a time (Pasricha et al., 2021).
Vitamins
- Vitamin D (25-OH): the main circulating form of vitamin D, which helps regulate calcium and phosphate for bones, teeth and muscles (in the Vitamin D test).
- Vitamin B12: a vitamin that, among other roles, keeps the nervous system healthy (in the Vitamin B12 test).
- Folate (vitamin B9): a B vitamin that works alongside B12 in making healthy red blood cells (in the Folate (Vitamin B9) test).
Thyroid
Both are in the Thyroid Function test.
- TSH (thyroid stimulating hormone): a hormone made by the pituitary gland that tells the thyroid how much hormone to produce.
- Free T4 (thyroxine): a thyroid hormone, measured in its free form, read together with TSH.
Liver
These are in the Liver Function Tests and in the Liver and Kidney Function Test. The American College of Gastroenterology suggests calling them liver tests or liver chemistries, since they reflect different processes rather than one single "function" (Kwo et al., 2017).
- ALT (alanine transaminase): one of the most commonly requested liver tests; with AST, it reflects the liver cells themselves.
- AST (aspartate aminotransferase): an enzyme read together with ALT; when both rise more than ALP, the pattern points to the liver cells.
- ALP (alkaline phosphatase): an enzyme that, when it rises more than ALT and AST, points to the flow of bile rather than the liver cells.
- GGT (gamma glutamyl transferase): a liver enzyme reported in the same panel and read alongside ALP.
- Bilirubin: a pigment the liver handles; a raised level can relate either to the liver cells or to the flow of bile.
- Albumin: a blood protein measured in the liver panel; the NHS lists protein tests among the ways to check the liver and kidneys.
