turnaround time (TAT)

Turnaround time is the elapsed time between two defined events in the laboratory service pathway. Possible starting points include test ordering, specimen collection, or laboratory receipt; possible endpoints include result authorization, release, or communication to the requester. A TAT value is meaningful only when these boundaries and the included examinations are stated clearly.

Agree targets with service users according to clinical need and distinguish urgent from routine pathways. Decide how referrals, added tests, rejected specimens, downtime, and repeat examinations are handled in the calculation. Review the distribution and delayed cases rather than relying only on an average, which can hide serious outliers. Reliable timestamps and consistent definitions are essential when comparing departments, periods, or different information systems used along the patient pathway.

For accreditation, TAT monitoring shows whether laboratory services support timely patient care. Targets should lead to action when delays arise, not merely to a monthly chart. Investigate where time is spent, assess the impact of late results, and verify that improvement efforts do not compromise identification checks, quality control, or appropriate result review and communication.