Comparison of Point of Care Hba1c Analytical Systems Against Laboratory Analysis Among Type 2 Diabetes Patients in Primary Health Centers in Riyadh

Abstract

Measurement of HbA1C, is widely used for routine monitoring of long-term glycemic status in patients with diabetes mellitus. The point-of-care (POC) HbA1c testing have been developed in the last years which allows rapid HbA1c determinations from capillary blood instead of conventional venous puncture, furthermore, the use of POCT for HbA1c in physician’s office leads to faster patient treatment and improved outcomes, including enhanced physician and patient satisfaction. Objectives: The aim of this study was to evaluate the accuracy of two point-of-care testing (POCT) analyzers  to be used on the regular HbA1c monitoring testing for type 2 diabetic patients at Primary Health Care Centers, by comparing their HbA1c results with the standardized laboratory testing. Method: A cross-sectional diagnostic study was conducted to compare the accuracy of two HbA1c point of care machines (DCA Vantage from Siemens and Afinion from Axis-Shield) with the Laboratory HbA1c reference standard. Consecutive, eligible, consented type 2 diabetic patients who were available at the laboratory for venous blood sample for standard HbA1c testing, one capillary puncture at the same visit was performed for analysis by the two HbA1c point of care testing instruments. Sample size for the five HbA1c levels strata (<7; 7-<8; 8-<9; 9-<10 & >10), was calculated in order to assess accuracy for each level. Results: A total of 246 Type 2 diabetic patients were recruited, and all had performed the 3 tests; the HbA1c reference standard, DCA Vantage HbA1c and Afinion HbA1c tests. The performance of POC devices, DCA and Afinion were compared to central laboratory HPLC method. Both POC devices showed strong positive correlations to Lab A1c with r = 0.98 (p < 0.01). The means difference for DCA was 0.002 SD 0.47 and P value 0.96, while it was 0.18 SD 0.41 and P value p < 0.001) for Afinion device. Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for DCA A1c compared with Lab A1c results at all levels were >93% except for NPV (85.7%). While, Sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for Afinion A1c compared with Lab A1c results at all levels were >=80%. Area Under the Curve (AUC) for DCA and Afinion was  > 0.90 Conclusion: Both DCA vantage & Afinion devices have strong positive correlation with central A1c testing, however DCA is superior in terms of accuracy.