Point-of-Care Assays for Hemoglobin A1c: Is Performance Adequate?

To the Editor:The routine measurement of hemoglobin A1c (Hb A1c)1 has become an essential component of the standard of care for patients with diabetes and has been recommended by major clinical diabetes organizations. A small amount of evidence shows that having the Hb A1c result at the time of the doctor's visit is beneficial (1). Recently, there has been discussion about whether the quality of point-of-care (POC) testing for Hb A1c is sufficient to meet clinical needs (2).The National Glycohemoglobin Standardization Program (NGSP) certifies methods annually at the manufacturer level, with only 1 lot of reagents being used at any point in time. Although College of American Pathologists proficiency testing provides an excellent snapshot of the performance of each method in the clinical laboratory, POC methods are CLIA waived; thus, users are not required to participate in proficiency testing. Inadequate performance of some of these methods in the hands of experienced users (2) has raised concerns about the ability of these methods to perform well enough for diabetes monitoring. The manufacturer of the A1cNow device (Bayer HealthCare) noted (3) that the use of EDTA-containing blood in …