A-142 Comparison of Alinity c Hemoglobin A1c Immunoassay with Premier Hb9210 Automated HPLC Assay: Very Few Patients May be Outside Reportable Range Using Alinity c.

Abstract

Abstract Background Hemoglobin A1c (HbA1c; glycosylated hemoglobin) is used for diagnosis and monitoring of patients with diabetes. In the clinical laboratory both immunoassays and high-performance liquid chromatography (HPLC) based tests are available for such measurement. We use Premier Hb9210 analyzer (HPLC method; Trinity Biotech, Jamestown, NY) for measuring HBA1c in whole blood. As our laboratory is transitioning to Abbott chemistry systems, we compared HbA1c values obtained by the Alinity c and Premier Hb9210. Methods The Premier Hb9210 analyzer is based on boronate affinity high performance liquid chromatography with output in 66 sec. The analytical measurement range is 3.8 to 18.5% although values as low as 2% can be reported by the analyzer but result may not be accurate. The Alinity c Hemoglobin A1c assay measures both total hemoglobin and HbA1c (enzymatic assay) in whole blood and then calculates %HbA1c. The analytical measurement range of this assay is 4 to 14% of HbA1c. Specimens cannot be diluted for Alinity c HbA1c measurement. Results Alinity c HbA1c has excellent total precision (0.4% at HbA1c of 5.1% and 0.25% at Hb A1c of 9.4%). In contrast, Premier HB9210 has total precision of 1.89% at HbA1c of 5.5% and 1.81% at HbA1c of 8.4%. However, analytical measurement range of Premier HB9219 is slightly wider compared Alinity c assay. Plotting HbA1c results obtained by the Premier Hb9210 analyzer in the x-axis and the corresponding values obtained by the Alinity c assay, we observed the following regression equation: y = 0.9499 x + 0.1108 ( n = 50, 0.99). The 95% confidence interval of the slope was 0.9241 to 0.9757. Rarely, we get specimen where HbA1c is between 3.8 and 4.0% (42 specimens out of 52 803 between 2/7/22 to 2/7/23; 0.08%) or above 14% (174 specimens out of 52 802; same period; 0.33%) and these specimens would not produce any result with Alinity c assay. We recently observed HbA1c result of 2.4 % in a sickle cell patient (reported as <3.8% per our lab policy). Discussion Our result indicates that HbA1c immunoassay on the Alinity c analyzer showed values comparable to HPLC method. However, for very few patients HbA1c may exceed 14% due to uncontrollable diabetes. Because specimen cannot be diluted, real value could not be measured using Alinity c but can be measured by the HPLC method. Conclusions We conclude that HbA1c assay on the Alinity c analyzer is a viable alternative to HPLC for measuring HbA1c in clinical laboratory. However, for very few patients (sickle cell trait, uncontrolled diabetes), HbA1c may be outside the range of Alinity c, requiring HPLC analysis.