Comparability of sample results and commutability of reference materials among different measurement procedures for protein C activity assays

Abstract

Background and aimsSeveral types of measurement procedures (MPs) for protein C activity assays are currently available. Clinical sample (CS) results among different MPs should be comparable. The commutability of reference materials (RMs) is an essential requirement to achieve comparability of CS results. Materials and methodsConsidering the total error calculated using reliable biological variation (BV) data and external quality assessment (EQA) criteria, we chose the allowable limits of comparability and criterion of commutability. According to Clinical and Laboratory Standardization Institute EP9 and our previous studies, 92 CSs were used to evaluate the comparability among the three MPs (Sysmex CS-5100, IL ACL TOP 700, and STA-R Evolution). The difference in bias method recommended by International Federation of Clinical Chemistry and Laboratory Medicine was used to assess the commutability of six RMs, including World Health Organization (WHO) IS 02/342. ResultsThe compliance rates of CSs were 94.6–100% with the corresponding calibration mode. WHO IS, HemosIL calibration plasma, and candidate RMs, PC20201 and PC20202, were commutable between each pair of the three MPs. ConclusionIt is feasible to set the allowable limits of comparability and the criterion of commutability based on the BV and EQA criteria.