title: Hb variants in Korea: effect on HbA1c using five routine methods.
abstract: BACKGROUND
  Quantification of glycated hemoglobin (HbA1c) is a challenge in patients with hemoglobin (Hb) variants. We evaluated the impact of various Hb variants on five routine HbA1c assays by comparing with the IFCC reference measurement procedure (RMP).
  
  
  METHODS
  Whole blood samples showing warning flags or no results on routine HPLC HbA1c assays were confirmed for Hb variants and were submitted to HbA1c quantification using Sebia Capillarys 2 Flex Piercing, Roche Tina-quant HbA1c Gen. 2, Bio-Rad Variant II Turbo 2.0, ADAMS HA-8180, Tosoh G8 standard mode, and IFCC RMP using LC-MS.
  
  
  RESULTS
  Among 114 samples, the most common variants were Hb G-Coushatta (n=47), Queens (n=41), Ube-4 (n=11), Chad (n=4), Yamagata (n=4), G-His-Tsou (n=2), G-Taipei (n=1), Fort de France (n=1), Hoshida (n=1), and two novel variants (Hb α-globin, HBA 52 Gly>Cys and Hb β-globin, HBB 146 His>Asn). In terms of control samples, all the result of HbA1c were "acceptable", within the criteria of ±7% compared to IFCC RMP target values. However, percentage of "unacceptable" results of samples with Hb variants were 16% for Capillarys 2, 7% for Tina-quant, 51% for Variant II Turbo 2.0, 95% for G8 standard mode, and 89% for HA-8180. The Capillarys 2 and HA-8180 assay did not provide the results in 5 and 40 samples with Hb variants, respectively.
  
  
  CONCLUSIONS
  HbA1c results from five routine assays in patients with relatively common Hb variants in Korea showed various degrees of bias compared to those of IFCC RMP. Therefore, laboratories should be aware of the limitation of their methods with respect to interference from Hb variants found commonly in their local population and suggest an alternative HbA1c quantification method.
authors.affiliation: .
authors.forename: Yeo-Min
authors.initials: YM
authors.lastname: Yun
authors.affiliation: .
authors.forename: Misuk
authors.initials: M
authors.lastname: Ji
authors.affiliation: .
authors.forename: Dae-Hyun
authors.initials: DH
authors.lastname: Ko
authors.affiliation: .
authors.forename: Sail
authors.initials: S
authors.lastname: Chun
authors.affiliation: .
authors.forename: Gye Cheol
authors.initials: GC
authors.lastname: Kwon
authors.affiliation: .
authors.forename: Kyunghoon
authors.initials: K
authors.lastname: Lee
authors.affiliation: .
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Song
authors.affiliation: .
authors.forename: Moon Woo
authors.initials: MW
authors.lastname: Seong
authors.affiliation: .
authors.forename: Sung Sup
authors.initials: SS
authors.lastname: Park
authors.affiliation: .
authors.forename: Junghan
authors.initials: J
authors.lastname: Song
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods* / Q000592:standards; D002851:Chromatography, High Pressure Liquid; D006442:Glycated Hemoglobin / Q000032:analysis* / Q000235:genetics*; D006801:Humans; D013058:Mass Spectrometry; D009154:Mutation; D012015:Reference Standards; D056910:Republic of Korea
chemical_list: D006442:Glycated Hemoglobin
keywords: HPLC; HbA1c; IFCC reference measurement procedure; capillary electrophoresis; immunoassay; variant hemoglobin