What is a reference range?

A reference range (also called a reference interval) is the set of values a lab uses to judge whether a test result is typical. It is usually built from results in a group of healthy people and covers the middle 95% of their values. That means about 1 in 20 healthy people will have a result just outside the range.

Reference ranges are not universal. They can differ between labs because of the analyzer, reagents and method used, and many tests have separate ranges by age, sex or pregnancy. That is why a report should always show the range the performing lab used next to each result.

Examples

Hemoglobin often has different ranges for adult men, adult women and children.
Some tests use a decision limit instead of a range, such as a cholesterol target or a cut-off for a positive screen.

A result outside the range is not a diagnosis. It is a prompt for the ordering clinician to look at the result in context.

How Lab Desk handles it

You set up your own tests, units and reference ranges once in the lab test catalog. When results are entered, Lab Desk checks them against those ranges and flags anything outside them for staff review.

Related terms

Abnormal flag: A marker such as H or L that shows a result falls above or below the reference range.
Critical value: A result so far outside the expected range that it may signal an urgent risk and must be reported to a clinician right away.
LIS (laboratory information system): Software that manages a clinical lab's orders, specimens, results and reports.

Reference range