Evaluation of the performance of the pre-analytical phase of the testing process in medical laboratory accreditation

Abstract

Aim: For the accreditation of a medical laboratory, it is necessary to evaluate the quality indicators (QI) used to evaluate pre-analytical process performance and establish an infrastructure to prevent errors arising from outside the laboratory. We aimed to present the quality indicators to prove the pre-analytical process performance of a medical (clinical) laboratory that has a large workforce prepared for medical laboratory accreditation.Methods: The sample rejection criteria were defined for the pre-analytical process. QIs, which are the requirements of the ISO15189 standard, was determined. QIs were estimated both as percentages and process Sigma levels. Pareto charts presented the distribution of errors.Results: QI values calculated as “%” and “Sigma” levels consistently demonstrated performances. According to 80% cumulated percentages, the Pareto charts rankings were “haemolysed,” “coagulated,” “barcode error,” and “insufficient” samples. In addition, when Pareto charts were evaluated, it was seen that the first 2 reasons in the 6-month period were “hemolysis” and “clotted samples” in all months. Still, the third most common reason was found to vary between “barcode error” and “insufficient” samples.Conclusion: Because of the consistency between % and sigma values, QIs can be presented with one of these in showing laboratory pre-analytical processes. However, sigma values give a more general view, and performance can be easily monitored between months. Pareto charts help illustrate error distribution and provide information for continuous improvement in laboratory-related healthcare.