Evaluation of Pre-Analytical, Analytical, and Post-Analytical Quality Indicators Before and After Laboratory Audit in a Tertiary Care Hospital

Background: One of the most effective ways of ensuring laboratory performance and patient safety is to use quality indicators (QIs) to monitor and analyze laboratory processes across the pre-analytical, analytical, and post-analytical stages of the total testing process. Periodic audits of laboratory operations can also identify any gaps in the operations and improve the laboratory’s quality management system. Methods: A prospective study was completed to examine laboratory QIs in a busy clinical laboratory from January through December 2025. QIs assessed through this study include sample rejection rate, reasons for sample rejection, re-testing rate, compliance with turnaround times (TAT), biologic alerts, and performance on external quality assessment (EQA) surveys. A laboratory audit was conducted in October 2025, and comparatives were made between laboratory quality indicators both prior to the laboratory audit and after the laboratory audit was completed. Statistical analysis was performed using the Chi-square test. Results: Overall, the study evaluated a total of 1,885,043 samples during the study timeframe. The rate of samples being rejected was consistently 0.14% (p=0.91) for both the pre-audit and post-audit periods of time. The rate of re-test testing was significantly elevated in the post-audit period (0.04% vs 0.06% p<0.001). The number of reports that surpassed the TAT measure decreased from 5.61% in the pre-audit period to 5.01% in the post-audit period (p<0.001). Clotted samples were the primary reason for a sample being rejected, accounting for 47.5% of the total sample rejections, while the second most common reason was due to the incorrect vacuum vial or barcode mismatch. The failed external quality assessment (EQA) tests percentage were also not statistically significantly different between pre-audit 4.91% and post-audit 7.55% (p=0.10). Conclusion: Continual assessment of laboratory quality indicators is essential to identify operational weaknesses and increase the overall quality of laboratory delivery and service. Periodic audits can also assist with optimizing the post-analytical period of laboratory delivery and compliance with TAT.