Critical Results in Laboratory Medicine

Timely and accurate notification of critical results is crucial in laboratory medicine and mandated by accreditation standards like ISO15189. Alert lists do, however, vary widely and clinical laboratories typically rely on a combination of in-house agreed and/or literature-based critical values. Communication by phone is still the preferred method of notification, but digital communication could help improve communication of critical results.

We review the available evidence concerning critical result thresholds and critical result notification practices. The evidence is ranked using an adaptation of the Stockholm Hierarchy. In addition, we propose an evidence-based list of critical result thresholds for hospitalized patients that laboratories can use as a starter list and further customize based on the clinical needs of their patient population.

A clear distinction between critical results and significantly abnormal results is essential for effective and timely healthcare interventions. Implementation of a policy using differentiated thresholds taking into account individual patient characteristics and how fast medical attention is needed, and the use alternative communication methods could enhance communication efficiency and reduce notification fatigue.