Laboratory and imaging
Critical value
A critical value is a laboratory result so far outside the expected range that it indicates an immediate risk to the patient's life, and it must be communicated to a responsible clinician without delay, with the notification confirmed and recorded.
Why it matters
A critical result that sits unread in a queue can mean a missed treatment window. Laboratories therefore agree a critical value list with clinicians, set a time within which a responsible person must be reached, and escalate when no one answers. A CDC review found that automated notification improves timeliness, while stressing two way acknowledgement and manual backup [1].
Key points
- Read back means the receiver repeats the patient identity, the test and the value to confirm the message.
- In a College of American Pathologists Q Probes study, 96 per cent of notification calls included read back [2].
- CLSI GP47 gives recommendations on critical result policies, reporting methods, escalation procedures and monitoring [3].
- Useful measures include time to notification and the proportion of notifications with documented read back.
In Moana
In MOANA LIS, critical values are flagged automatically, notification and read back are recorded against the result, and the verified result is visible in the patient chart.
Sources
- Effective practices for the timely and accurate reporting of laboratory critical values, Centers for Disease Control and Prevention, 2012
- Good news on critical values, says Q Probes audit: study findings in brief, CAP Today, College of American Pathologists, 2008
- CLSI publishes a new document on management of critical and significant risk results, Lab Medicine Blog, 2015
Read the guide: Critical Value Reporting in the Laboratory: Closing the Loop
In the platform: MOANA LIS
Related terms: Laboratory information system, Clinical decision support, Audit trail
Updated 2026-11-03. Written under Moana’s editorial standards.