Sigma metric performances of Capillarys 3 Tera and Premier Hb9210 HbA1c analysers and comparison of conventional...

This study was carried out to estimate sigma values of two HbA1c analysers and compare laboratory's quality control (QC) procedure with a patient risk based statistical quality control (SQC) strategy.

Internal quality control (IQC) and External quality control (EQC) results are downloaded from the laboratory data for different six-months' period when each analyser was used in the laboratory. Mean percent coefficient of variation (CV) and bias values of study period were calculated. Sigma values for each system were calculated. QC constellation program was used for risk-based QC parameters calculation and severity of harm level for HbA1c was taken as 'serious'.

Sigma values for Capillarys 3 Tera analyser (Captera) were 3.83 and for Premier Hb9210 analyser (Premier) were 2.95. Using ±2 standard deviation (SD) as control limits; on Captera with a run size of 110 samples, probability of false rejection rate (Pfr) was 8.89%, expected maximum unreliable patient results (Max E(Nuf)) was 0.78 and on Premier analyser with a run size of 800 samples Pfr was 8.89% and Max E(Nuf) was 40.73. Effective statistical quality control strategies for both systems with acceptable Pfr and affordable Max E(Nuf) are provided in the study.

HbA1c is a key parameter in diabetes management and accurate methods are required for an efficient clinical use.