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.
Result on your report
IllustrativeExample result
5.4
Range: 4.0 – 5.6
Basics
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.
Variability
Why ranges differ
Reference intervals are not universal. Prefer the range printed on your report over a range from the internet.
Reference ranges vary between laboratories. Learn more
Practical use
How to use ranges wisely
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
Next step
Keep the report with the range
Upload lab reports you already have. When you organize history, preserving source ranges avoids mixing intervals from different laboratories.