Effect of the different assays of HbA1c on diabetic patients monitoring

BACKGROUND: HbA1c test is widely used for glycemic monitoring of diabetic patients. This study aimed to evaluate clinical performance of different assays for classification of patients into controlled and uncontrolled group base on ADA recommendations. METHOD: A total of 154 samples from patients with diabetes type 2 with HbA1c concentration covering the whole clinical range were analyzed by four commercially methods; D-10 Hb A1c (Bio-Rad Laboratories), Cobas Integra 400 (Roche Diagnostics), NycoCard Reader II (Axis-Shield) and DS5 (Drew Scientific). For each individual assay, patient’s results were classified into controlled and uncontrolled groups (less or more than three decision levels; 6.5 %, 7 % and 8 %) compared to D10 results as reference method. The frequency of each group and also sensitivity, specificity, negative and positive predictive value were estimated. RESULTS: We found a significant correlation between assays (r: 0.937–0.945). Sensitivity, specificity, and positive and negative predictive values of the evaluated method to identify uncontrolled patients were as follows: 49.2–95.7 %, 86.5–100 %, 89.1–100 %, and 52.9–93.3 %; respectively. CONCLUSIONS: Results show that some HbA1c assays capability to classify diabetic patients according to HbA1c level is still unacceptable.