Monitoring glycaemic control: is there evidence for appropriate use of routine measurement of glycated haemoglobin?

Abstract

Regardless of the available recommendations to perform glycated haemoglobin testing at a 2- to 3-month frequency, there is increasing evidence of an inappropriate laboratory use of this test in clinical practice. Data from our Laboratory Information System were analysed for glycated haemoglobin test orders over a 3-year period using Microsoft Excel to calculate the order intervals and the test frequency for each patient. To assess the appropriateness of repeat testing, only data for patients who had at least two separate glycated haemoglobin test results were included in the analysis. Inappropriate test orders were defined as any order for a given patient taking place within a 29- or 89-day period following the previous order. The results of our investigation demonstrate that inappropriate laboratory utilisation of this test is commonplace (26% of total repeat orders within 90 days), especially for inpatients (63.7% of inpatient repeat orders in less than 90 days). When stratifying glycated haemoglobin test results according to the >7% threshold, the frequency of inappropriate laboratory use (>90 days) was surprisingly greater among inpatients with a previous value of <7% than among those with a previous value of >7% (57.6% vs. 42.4%). The frequency of inappropriate glycated haemoglobin repeat test orders was lower among outpatients with a previous value of <7% than in outpatients with a previous value of >7% (64.8% vs. 35.2%). We conclude that more accurate application of the current recommendations would be advisable to decrease unnecessary testing and prevent avoidable health expenditure.