The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts

PERFORMANCE EVALUATION OF THE EPOC BLOOD GAS SYSTEM

Robert Chatburn1, Robert Chatburn1



Background: EPOC (Epocal Inc., Ottawa, ON) is a new point of care blood testing system comprised of blood test cards based on smart card technology and card readers which are wirelessly connected to hand-held PDAs. The purpose of this study was to evaluate the system's performance compared to analyzers currently in use at our hospital.

Methods:
Experiments were conducted using National Committee for Clinical Laboratory Standards guidelines (NCCLS EP6-A, EP10-A2, EP9-A2). Data were collected using two EPOC systems, 4 Radiometer ABL 700 series and 1 Radiometer ABL 800 series. Calibration verification was conducted before the experiment according to manufacturers' guidelines. Blood samples were obtained from patients and were run on the ABL by Cleveland Clinic personnel and on the EPOC by Epocal personnel. Precision Experiment: measurements were performed on two control levels for each analyte using the EPOC systems. Testing was on two daily occasions, each in duplicate, over a period of 5 days, for a total of 20 replicates. Method Comparison Experiment: A total of 55 blood samples were collected, each split into 4 aliquots. Two aliquots were analyzed on ABLs and two on EPOCs. Data were analyzed with NCCLS procedures and Bland-Altman plots. Differences between Radiometer machines (within systems) were compared to differences between Radiometer and EPOC machines (between systems; EPOC minus Radiometer) with Mann-Whitney Rank Sum tests with P<0.05 considered significant.

Results:
Results of the NCCLS and Bland-Altman analyses are shown in Table 1. Comparisons of within vs between system median differences were significant for pH (0.002 vs -0.02), PCO2 (-0.6 vs 0.8), Na+ (0.0 vs -1.0), K+ (0.0 vs -1.0), Ca++ (0.00 vs -0.01), and Hgb (0.00 vs -0.40) but not for PO2 (0.2 vs 0.5).

Conclusion:
Comparison of within system results to between system results indicates that the two systems are not equivalent. However, while the differences between the EPOC and Radiometer machines is generally larger than that expected between two Radiometer machines, the differences may be clinically unimportant.