Trusted-source health topic
Understanding Laboratory Reference Ranges
A reference range describes values found in a defined reference population using a particular laboratory method.
Why is this important?
Understanding the purpose and limits of laboratory information can support a more informed conversation with a qualified healthcare professional.
How laboratory testing relates
A value inside or outside a range is not a diagnosis by itself. Professionals interpret it with the test method, individual context, and other information.
Before testing
Preparation is test-specific. Follow the instructions given for the exact test and contact the laboratory if fasting, timing, medicines, or specimen collection is unclear. Do not stop medicines unless a qualified professional tells you to.
Sources & further reading
- MedlinePlus, U.S. National Library of Medicine: How to Understand Your Lab Results
External authoritative patient reference · Verified 2026-08-10