Pre-analytical phase errors constitute the vast majority of errors in clinical laboratory testing

Clinical laboratory errors pose a threat to patient safety and previous studies have demonstrated that pre-analytical error is the most common error type. Our study aimed to determine the types and frequency of errors occurring in clinical laboratory testing in contemporary practice.

Errors occurring in a core laboratory between 01/2022 and 05/2023 were recorded retrospectively. Errors were quantified using multiple data-streams including real-time manual technologist intervention, incidence reports filed by hospital staff/physicians, and retrospective assessment using automated reports from the lab information system (LIS). Errors were adjudicated and binned into pre-analytical, analytical, and post-analytical phases. Total test volumes were assessed in the LIS and electronic medical record.

There were 37,680,242 billable results reported from approximately 11,000,000 specimens during the study period. In total, 87,317 errors occurred impacting 0.23 % (2,300 ppm) of billable results and approximately 0.79 % (7,900 ppm) of specimens. Among these errors, 85,894 (98.4 %, 984,000 ppm) were in the pre-analytical, 451 (0.5 %, 5,000 ppm) were in the analytical, and 972 (1.1 %, 11,000 ppm) occurred in the post-analytical phase. Hemolysis impacting specimen integrity (60,748/87,317, 69.6 %, 696,000 ppm) was the most common error. When excluding hemolysis, there were 26,569 errors documented (0.06 %, 600 ppm of billable results), among which 94.6 %, 1.7 % (17,000 ppm) and 3.7 % (37,000 ppm) were in the pre-analytical, analytical and post-analytical phase respectively.

Observed error rates were consistent with previous studies with pre-analytical errors comprising most errors. High prevalence of pre-analytical errors implies a need for enhanced tools for error detection and mitigation in the pre-analytical phase of testing.