HbA1c testing frequency

With the dramatic rise in the prevalence of diabetes comes an associated increase in the amount of HbA1c testing that is required. Current estimates indicate that there is an average annual increase of 8-10% in workload in medical laboratories. In Ontario during 2011 and 2012, the total number of HbA1c tests completed was 3.4 million with an associated cost of $30 million dollars. This is an increase of 55% from 2007-2006 where a total of 2.2 million tests were completed.3 During the same period 1.4 million HbA1c tests were conducted in non-diabetic patients. It has been estimated that the health related expenditures for patients with diabetes are at least 2.4 times higher than those for non-diabetic patients. This brings to the forefront the need to determine an optimal frequency for HbA1c testing in order to manage both healthcare budgets and productivity. While published guidelines have described treatment goals and give minimum limits for testing frequency there is a lack of defining criteria for the maximum number of tests or the optimal testing frequency for ideal control. In addition to this problem, previous studies demonstrate that testing is used in patients who do not require it, such as in those who are not diabetic, and those who have had no history of problems with glycemic control. HbA1c testing is typically done twice yearly in well controlled patients and four times yearly in poorly controlled individuals. Studies have shown that both over and under-utilization trends are commonplace in clinical practice. For example it has been found that some individual patients have received a total of 28 HbA1c tests in a single year. The reverse of this has also been found where individual patients are only tested one time in a two year long period. The purpose of this report is to examine the evidence on the effect of different testing frequencies for HbA1c and discuss the guidelines governing the timing of use.