[Comparison of glycosylated hemoglobin and oral glucose tolerance test in diagnosis of diabetes in person withimpaired fasting glucose]

ABSTRACT

Glycosylated hemoglobin gives an average plasma glucose level over the past two to three months period. Diabetes is one of the most important causes of mortality and morbidity in the old ages, that usually due to it's slow progress, patients do not pay attention to the disease. Early diagnosis can decrease many complications. This investigation is carried out with the aim of comparison results of FBS, GTT and HbA[1]c especially in persons with impaired fasting glucose.Our study is a cross sectional analytical study. 81 persons, 40 to 65 years old, without any history of diabetes, with FBS 103 to 140mg/dl were selected according to convenience sampling method. FBS, GTT and HbA[1]C tests were done for all samples. Sensitivity, specificity, positive predict value and negative predict value of tests were determined.In this study comparison of HbA[1]C with FBS showed 100% sensitivity and 12.5% specificity, with positive predict value of 82% and negative predict value of 62.7%. In comparison of HbA[1]c with GTT, we observed 100% sensitivity and 63% specificity with positive predict value of 6.3% and negative predict value of 100%. In the other part of this investigation in comparison of FBS with GTT, 9.7% sensitivity and 100% specificity and positive predict value of 100% and negative predict value of 18.8% was reported.According to results of the present study, due to very high sensitivity and significant positive predict value of HbA[1]C as compared to FBS, HbA[1]C measurement seems to be a good test in screening and diagnosis of diabetes. Therefore, in impaired fasting glucose, we recommend measurement of both HbA[1]C and FBS. Also HbA[1]C can be used as a good replacement test for GTT in person with impaired fasting glucose