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Six of Eight Hemoglobin A_1c Point-of-Care Instruments Do Not Meet the General Accepted Analytical Performance Criteria

¹ Department of Clinical Chemistry, Isala klinieken, Zwolle, The Netherlands; ² European Reference Laboratory for Glycohemoglobin, Zwolle, The Netherlands.

^aAddress correspondence to this author at: Isala klinieken, Department of Clinical Chemistry, Groot Wezenland 20, 8011 JW Zwolle, The Netherlands. Fax +31-38-4242-676; e-mail w.b.lenters{at}isala.nl.

Background: Hemoglobin A_1c (Hb A_1c) point-of-care (POC) instruments are widely used to provide rapid-turnaround results in diabetic care centers. We investigated the conformance of various Hb A_1c POC instruments (In2it from Bio-Rad, DCA Vantage from Siemens, Afinion and Nycocard from Axis-Shield, Clover from Infopia, InnovaStar from DiaSys, A1CNow from Bayer, and Quo-Test from Quotient Diagnostics) with generally accepted performance criteria for Hb A_1c.

Methods: The CLSI protocols EP-10, EP-5, and EP-9 were applied to investigate imprecision, accuracy, and bias. We assessed bias using 3 certified secondary reference measurement procedures and the mean of the 3 reference methods. Assay conformance with the National Glycohemoglobin Standardization Program (NGSP) certification criteria, as calculated from analyses with 2 different reagent lot numbers for each Hb A_1c method, was also evaluated.

Results: Because of disappointing EP-10 results, 2 of the 8 manufacturers decided not to continue the evaluation. The total CVs from EP-5 evaluations for the different instruments with a low and high Hb A_1c value were: In2it 4.9% and 3.3%, DCA Vantage 1.8% and 3.7%, Clover 4.0% and 3.5%, InnovaStar 3.2% and 3.9%, Nycocard 4.8% and 5.2%, and Afinion 2.4% and 1.8%. Only the Afinion and the DCA Vantage passed the NGSP criteria with 2 different reagent lot numbers.

Conclusions: Only the Afinion and the DCA Vantage met the acceptance criteria of having a total CV <3% in the clinically relevant range. The EP-9 results and the calculations of the NGSP certification showed significant differences in analytical performance between different reagent lot numbers for all Hb A_1c POC instruments.

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