ASSESMENT OF THE ANALYTICAL PERFORMANCE OF 11 MEASURED AND 3 CALCULATED ANALYTES USING THE EPOC® BLOOD ANALYSIS SYSTEM

Background: This study aimed to evaluate the analytical performance using the Epoc® Blood Analysis System for 11 directly measured (pH, pCO2, pO2, Na+, K+, iCa2+, Cl-, Glu, Lac, Crea and BUN) and three calculated analytes (HCO3-, BE and sO2).
Material and methods: The coefficient of variation (CV%) was calculated based on a between-day replication study using internal quality control material at two concentrations measured once a day. The relative mean difference (BIAS%) was calculated based on method comparisons of 53 to 55 paired arterial patient samples (heparin whole blood) using ABL 835 Flex Blood Gas Analyzer (Radiometer) and Dimension Vista 1500 System (Siemens Healthineers). The total analytical error (TAE%) was estimated by calculation of the 95% confidence interval, which incorporates the observed CV% from the replication study and BIAS% from the method comparison study.
Each analyte’s precision, trueness and accuracy were assessed by comparing the observed CV%, BIAS% and TAE% to the analytical performance specifications (APS) from Westgard for imprecision (I%), bias (B%) and total allowable error (TE%), respectively. The analytical performance using the Epoc were considered acceptable in clinical settings if at least the minimum specifications for accuracy were achieved.
Results: pH, BE, K+, Glu, Lac and BUN fulfilled the minimum specifications for precision, while pCO2, HCO3-, Na+, Ca+, Cl- and Crea did not. pH, pCO2, BE, Na+, K+, Glu, Lac and BUN fulfilled the minimum specifications for trueness, while HCO3-, iCa2+, Cl- and Crea did not. pH, pCO2, BE, K+, Glu, Lac and BUN fulfilled minimum specifications for accuracy, while iCa2+ did not. No performance criteria were specified for pO2 and sO2.
Conclusions: pH, pCO2, BE, K+, Glu, Lac and BUN showed analytical performances acceptable for use in clinical settings using the Epoc Blood Analysis System since minimum specifications regarding accuracy were achieved. iCa2+ showed unacceptable analytical performance for use in clinical settings, whereas the results for HCO3-, Na+, Cl- and Crea were inconclusive.