Within-clinic glycosylated haemoglobin measurement

The performance of the Diamat HPLC analyser (Bio Rad Instruments) was assessed, and the effect of this on-site HbA1 assay on the therapeutic decisions made at the diabetic clinic evaluated. The intra-assay CV for HbA1 at concentrations of 8.3 and 13.4% was 3.8 and 0.4%, respectively, with inter-assay CV of 5.0 and 3.0%. On a single day 82 HbA1 tests on consecutive patients were performed at the clinic. In 43 insulin-treated patients and 79 non-insulin-treated diabetic patients the HbA1 result changed the management decision in 25 and 18% of patients, respectively. The relationship between HbA1 and self blood glucose monitoring (SBGM) results in the previous 6-week period were also evaluated. In 41% of patients with insulin-treated diabetes who produced SBGM diaries there was a discrepancy between categories of blood glucose control, all of these patients having better SBGM than HbA1 values. This study highlights the feasibility and value of a within-clinic HbA1 assay for clinical decision-making and its usefulness in identifying problems of agreement with self-monitored tests.