The use of HbA1c as a screening tool for the diagnosis of diabetes mellitus in a local South African community

Abstract

HbA1c has been the gold standard measurement of chronic glycaemia for over two decades. Diabetes mellitus (DM) may be diagnosed using WHO or ADA criteria – both use either a 2 hour or a fasting glucose level. This would require a fasting sample, thus leading to inconvenience for the patient and requiring an early morning appointment with the physician. There is a need for a more convenient screening test for DM or impaired glucose tolerance (IGT), which can be performed on a random blood sample. For a test to be an effective screening tool, a high sensitivity is required. Previous problems with HbA1c assay standardization, as well as its large biological variation, meant that it was not an effective screening tool. However, with the recent advances in standardization of the assay, there have been suggestions that HbA1c may be an effective screening tool.