The Value of HbA1c that gives a good yield for Screening

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Devon Science Publication


HbAlc is being used as a screening toot for diabetes with its performance varying in different studies depending on the cut-off point of HbA1c used and the reference gold standard. To determine the level of HbA1c that defines the best cut-off point compatible with maximum yield using 2hours post 75gram glucose as reference. A cross sectional study of 207 patients with systematic hypertension attending the renal and cardiology out patient clinics of the Lagos University Teaching Hospital were recruited. One hundred and thirty one (131) of the subjects had OGTT done. A random sampling method was to select one out of every four who had HbAlc done using DCA 2000r autoanalyzer. Receiver Operating Characteristic Curve was plotted to determine the appropriate HbAlc cut-off point that gave optimal sensitivity and specificity for the diagnosis of diabetes using plasma venous glucose, 2 hours post 75gram OGTT. A 2x2 table was utilized to determine the predictive value, and efficiency of the HbA1c cut-off point for the diagnosis of diabetes. HbA1c cut-off point of 6.7% was found to give sensitivity of 57.14%, specificity of 75%, positive predictive value of 36.36%, negative predictive value of 85% and efficiency of 67.74%, the new cut-off point of HbA1c has improved the performance of the method as a screening tool.



Diabetes, Screening, Glycated hemoglobin (HbA1c), Oral Glucose Tolerance Test and Receiver Operating Characteristic Curve


African Journal of Medical and Pharmaceutical Sciences