Blood proficiency testing as an external quality control of the laboratory performance

Abstract

Objective. To compare the results obtained from the participation in a blood proficiency testing study (B-PTS) in order to assess the corrective measures towards improving blood safety undertaken in the transfusion-transmissible infection (TTI) testing laboratory. Methods. The B-PTS study was designed, organized and conducted by European directorate for the quality of medicines (EDQM). The 3 laboratories for TTI testing participated in 2017 and 2018 by testing the B-PTS samples and reporting the results on the online result data sheet. Each laboratory performed TTI testing on a set of B-PTS-samples contained 4 panels: anti-HCV, anti-HIV/p24, anti-Treponema and HBsAg panel. The samples were subjected to serological testing with two assays: enzyme immunoassay with Enzygnost system, Siemens using BEP2000 and chemiluminescent microparticle immunoassay with Architect system, Abbott using Architect i2000. Results. In 2017, the performance of all of the participating laboratories was classified as “satisfactory” for B-PTS anti-HCV and anti-Treponema panel. For B-PTS anti-HIV/p24 panel the classification was “non evaluable” because the results were not properly submitted. The B-PTS HBsAg results were classified as “unsatisfactory” because two laboratories reported nonconforming result for one of the reactive samples from the panel, one laboratory with the Enzygnost assay and one laboratory with the Architect assay. The single observed non-conformity was that the S/Co (1.22) of the positive control for the Architect HBsAg assay was out of rang (1.65-4.96) for the corresponding reagent lot. As a corrective measure additional training of the staff was introduced and a decision was made for each laboratory to send the results and the correspondent interpretations itself in order to avoid the previous technical errors. In 2018, the performance of all of the participating laboratories was classified as “satisfactory” for each of the B-PTS panels. Conclusion: The participation in a B-PTS study provides an objective and independent evaluation of the overall performance of the laboratory aimed to detect non-conformities and to undertake corrective measures. This is an excellent tool for external control of the quality of laboratory testing which is necessary for further improvement of blood safety concerning TTI.