Reference Interval of Glycated Hemoglobin in Adults in Port Harcourt, Nigeria

Background: Measurement of glycated haemoglobin is accepted as the gold standard for the diagnosis and management of diabetes mellitus; but it is rarely used in this environment, a resource-poor setting, largely due to the high cost of the assay. There is need to determine its reference intervals in Port-Harcourt and encourage the use of this assay.

Aim:This study was designed to determine the reference interval of glycated haemoglobin of apparently healthy subjects between the ages of 20-80 years in Port Harcourt, Rivers State, Nigeria.

Methods: A total of 172 subjects who met the inclusion criteria were recruited for the study. A cross sectional sampling method was used to recruit subject. Subjects’ past medical history, demographic and anthropometric information were obtained with the help of a questionnaire. Blood was collected from subjects into an EDTA bottle and analysed for glycated haemoglobin using the boronate affinity chromatographic method.

Results: Results were analyzed using Statistical Package for Social Sciences version 20.0 (SPSS 20.0) and the reference interval was determined by the nonparametric method due to the skewness of the data. The mean age of subjects was 35.4 years and the minimum and maximum glycated haemoglobin value obtained were 3.5% and 6.0% after eliminating outliers. This gave a mean glycated haemoglobin value of 4.84% and a reference interval of 4.0-5.9%.

Conclusion: The reference interval so determined (4.0-5.9%) is different from that generated by the manufacturer of the diagnostic kit(4.0-6.5%). The introduction of this new local reference interval will enhance patient management in our local hospitals.