A-161 Evaluation of Precision and Reproducibility of the ExpertCor Routine Plasma Sample Set Across Coagulation Test Platforms

Abstract Background In College of American Pathologists (CAP) accredited and good laboratory practice (GLP)-compliant laboratories, determination of reproducibility between systems is critical for method comparison and reference range determination. Demonstration of assay comparability in accordance with ISO 15189:2012 and other local guidelines is an increasing challenge for all laboratories, especially with the impact of labor and resource shortages impacting daily practice. Laboratories must validate assays across multiple platforms and sites within a standardized health network, ensuring ongoing assessment and method verification where necessary, especially during reagent lot conversion. We conducted a study to evaluate precision of ExpertCor Routine (ECR), a commercially available plasma sample set, designed for validation across different analyzers and laboratories. The data not only help to demonstrate suitability of the product in laboratories purchasing the product, but also allow us to meet regulatory guidelines for in vitro diagnostic (IVD) manufacturers. The aim of our study was to assess the precision of four coagulation test parameters in a set of 35 plasma samples comprising the ECR kit, spanning a clinically relevant range. Methods Precision testing was conducted over 20 days, generating 80 test results per sample for PT (sec)/INR, aPTT (sec), and fibrinogen concentration. Testing was performed on STA-R Evolution and STA-R Max3 analyzers using STA Neoplastine CI Plus, STA PTT A, and STA Fibrinogen reagents (Diagnostica Stago, Inc.). A single validation lot of ECR kits was used, with samples tested in duplicate by different operators in morning and afternoon sessions. Mean daily coefficient of variation (%CV) values were calculated for each test parameter, with an overall acceptance criterion of = 5%. All tests were performed using the manufacturer’s recommended protocols by certified operators. Results The mean daily %CV for PT, INR, aPTT, and fibrinogen remained below 5.0% throughout the study. The overall mean %CV for the ECR kits over 20 days was at 2.2, also below 5.0%: demonstrating consistent precision. Observed precision results are attached as supporting figure/file. Conclusions: ECR sample vials exhibited high precision and reproducibility, confirming its suitability for lab-to-lab, system-to-system, and lot-to-lot comparisons. These findings support the reliability of the ECR kits as a validation and verification tool for clinical laboratories. By use of the ECR kit, laboratories can reduce the need for specimen collection and optimize local reference interval determination process by application of transference principle (CLSI guideline E28-A3c, section 10). In daily practice, the generated metrics from use of the ECR kits can be compared directly with acceptance criteria to document their compliance in accordance with the local process.