A Cross-Sectional Comparison of Point-Of-Care A1CNow+ Machine with Laboratory HbA1c in Detecting Diabetes in Urban Communities, South Trinidad, 2019–2020

Abstract Background: About 30% of the Trinidad and Tobago (T and T) population has undiagnosed type 2 diabetes mellitus (T2D). This study aimed to determine if point-of-care (POC) glycated hemoglobin (HbA1c) is sufficiently accurate in a real-world setting to screen and diagnose T2D compared with hospital-based laboratory HbA1c measurements. Materials and Methods: This was a descriptive, cross-sectional study comparing POC capillary results with corresponding venous HbA1c levels measured in a hospital-based laboratory. Eighty eligible participants from urban grocery stores in South Trinidad were enrolled via convenience sampling. Sensitivity, specificity, predictive values, concordance, and mean differences between POC blood HbA1c measurement and laboratory measurement of venous HbA1c levels for diagnosing and screening for diabetes. Concordance was determined by the technique of Lin. The mean difference and limits of agreement were determined using the techniques of Bland and Altman. Results: The concordance between POC and laboratory results was good ( P < 0.001). The mean difference was −0.125% (95% limits of agreement, −0.878 to 0.628%). POC HbA1c measurements of >6.4%, 48 mmol/mol had a specificity of 98.6% and a sensitivity of 77.8% for laboratory measurements of >6.4% for diagnosis of T2D. The POC equivalence value for screening for diabetes or a high risk of developing T2D was ≥5.7%, 39 mmol/mol (sensitivity, 83.3%; specificity, 72.6% for laboratory measurements of ≥6.0%, 42 mmol/mol). Staff were trained in-house to use the POC HbA1c analyzer. Conclusions: POC HbA1c testing has a high predictive value and is a useful component in screening for and diagnosing T2D in remote communities.