EP15A3 Based Precision and Trueness Verification of VITROS HbA1C Immunoassay

Verification of analytical performance of measurands becomes an essential requirement for the laboratories before proceeding to patients' samples testing. In our study we have verified the performance of HbA1C Immunoturbidimetric assay (VITROS 5600) against manufacturers' claims using CLSI EP15A3 Guidelines. We performed our study using two concentrations of Quality Control from Bio-Rad (Level 1 and Level 2). A precision verification study was carried out using five replicates of QC per day for five days following which imprecision estimates in form of Within Run (Repeatability) %CV and Within Lab %CV were calculated and compared against manufacturer's claims. Second part of our study included derivation of grand mean from the results of 25 replicates of QC used for precision verification. This was compared against the Target Value of the assigned QC obtained from the peer group mean of laboratories participating in interlaboratory QC program (unityTM Interlab-Bio-Rad) for %bias estimation. The findings of our precision study showed an acceptable Within Lab imprecision (%CV_WL-0.6%), while the %CV -repeatability (%CV_R-0.54%) was greater than the manufacturer's claim (σR-0.5%). Hence upper verification limit for the manufacturer's claim (0.65%) was calculated against which the %CV Repeatability was compared and was found to be acceptable. The trueness verification showed that our grand mean (5.488%) was within the verification interval of the target value (5.462-5.497%) and hence the actual %bias was not statistically significant. Our study demonstrates that HbA1C immunoassay shows an acceptable performance consistent with the manufacturer's claims.