Education
What is a lab reference range?
Reference ranges help frame a single result — but they are not universal, and being outside a range is not automatically a diagnosis.
The short answer
A reference range (sometimes called a reference interval) is the span of values a laboratory expects for a given test method in a defined population. Your report usually prints the range next to your result.
Why ranges differ
- Different instruments and chemical methods
- Different populations used to establish the interval
- Age, sex, or other reporting conventions on some tests
- Updates when a lab changes methods
Reference ranges vary between laboratories. Learn more
How to use ranges wisely
- Prefer the range printed on that report over a range from the internet
- Ask your clinician before assuming “out of range” means something urgent
- When comparing over time, note whether the lab or method changed
General biomarker education — not personalized medical advice. Learn more