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Blood test glossary
Plain-English definitions of common blood test terms — reference range, fasting, panel, biomarker, units and more — with links to detailed pages.
Written by LON6EVITY Editorial Team · Last updated
Biomarker
A measurable substance or signal in the body, such as cholesterol or glucose, that gives information about health or disease risk.
Reference range
The range of results seen in most healthy people, set by each laboratory. MedlinePlus notes that ranges can differ between labs and that a result outside the range does not always mean a problem. Always compare with the range printed on your own report.
Panel
A group of tests ordered together, for example a lipid panel (cholesterol and triglycerides) or a metabolic panel (glucose, electrolytes and kidney markers).
Fasting test
A test for which you are asked not to eat or drink anything except water for a set time beforehand, commonly 8–12 hours. Follow the instructions you are given.
Units
Results are reported in units such as mg/dL or mmol/L. Different countries use different units, so the same value can look very different. Compare only results in the same unit.
False positive and false negative
A false positive suggests a problem that is not there; a false negative misses one that is. This is one reason tests are interpreted with symptoms and history.
Related biomarkers
Related tests
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Build your longevity profile
What does this mean for your own health data? Log your results, follow trends over time and bring an organised summary to your next doctor's appointment.
Sources
- Lab tests. MedlinePlus (NIH).