Glossary
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.
What is a critical value in the lab?
A critical value (sometimes called a panic value or critical result) is a test result far enough outside the expected range that it may point to an urgent, possibly life-threatening condition. It needs to reach a responsible clinician quickly so they can act.
Each lab keeps its own list of critical limits, usually agreed with the clinicians it serves. Common examples include very high or very low potassium, glucose or platelet counts.
How labs usually handle them
- A written policy that lists critical limits and who to call.
- Direct contact with the ordering clinician or care team, often by phone.
- A read-back, where the person receiving the result repeats it to confirm it was heard correctly.
- A record of who was told, when, and by whom.
In the US, CLIA requires labs to have a procedure for promptly alerting the right person when a result indicates imminent danger. Accrediting bodies also review how quickly critical results are reported.
How Lab Desk handles it
Lab Desk flags results outside your reference ranges and lists them for review first, so urgent values are easy to see. Your lab's own critical value policy, including who to call, stays with your team. See AI flagging.
Related terms
- Abnormal flag: A marker such as H or L that shows a result falls above or below the reference range.
- Reference range: The span of test values expected in a healthy reference population, used to judge whether a result is typical.
- CLIA: The US federal rules that set quality standards for labs testing human specimens for health care.
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