To the Editor: Lenters-Westra and Slingerland (1) recently reported results of a comparative performance study of several point-of-care (POC)1 tests for hemoglobin A1c (Hb A1c), and we commend them for providing useful new information on instrument performance. We also believe that the results should be interpreted strictly in terms of the facts, including consideration of discrepancies between the study design and the instructions provided by the manufacturers. Bayer's A1CNow+® Multi-Test A1C System was included in the initial phase of this study, but testing was not continued for the main phase of the study after the local distributor of that product concluded that the preliminary CLSI EP-10 results did not warrant further testing. The authors reported that these results were probably due to EDTA interference. As a POC test, the A1CNow+ test is primarily intended for capillary blood samples, and the instructions for use specify use of heparin- containing collection tubes when using venous blood. The authors' title, “Six of Eight Hemoglobin A1c Point-of-Care Instruments …