title: Haemoglobin A₁c measurement in patients with chronic kidney disease.
abstract: OBJECTIVE
  The aim of this study is to investigate the interference of carbamylated haemoglobin (cHb) to haemoglobin A1c (HbA₁c) measurements in patients with chronic kidney disease (CKD) by three ion-exchange chromatography methods.
  
  
  METHODS
  We included three ion-exchange chromatography methods (Bio-Rad Variant II, G7 and HA-8160) and one affinity chromatography method (Primus Ultra2) to test HbA₁c. In vitro carbamylation of haemoglobin was also performed to test interference of carbamylation.
  
  
  RESULTS
  152 CKD patients were diagnosed. The average HbA₁c and urea levels of nondiabetic and diabetic patients were 5.24% (33.8 mmol/mol) and 7.36% (56.9 mmol/mol) and 16.2 mmol/L and 11.2 mmol/L, respectively. Repeated measures ANOVA showed that the difference of HbA₁c values between four methods is not statistically significant (P=0.421 for non-DM and P=0.336 for DM). With the increase in blood urea concentration from stage 3 to stage 5, there was no corresponding increase in HbA1c values for both groups. In vitro carbamylation results showed that carbamylated Hb peaks could be clearly identified by the three ion-exchange methods.
  
  
  CONCLUSIONS
  HbA1c measurement by these methods may not be impacted by carbamylated Hb. The results should be interpreted with caution in high carbamylated Hb patients.
authors.affiliation: Shanghai Centre for Clinical Laboratory, Shanghai, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.affiliation: Shanghai Centre for Clinical Laboratory, Shanghai, China. Electronic address: juyi@sccl.org.cn.
authors.forename: Yi
authors.initials: Y
authors.lastname: Ju
authors.affiliation: First Hospital of Fuzhou, Fujian Province, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Jin
authors.affiliation: First Hospital of Fuzhou, Fujian Province, China.
authors.forename: Biqiong
authors.initials: B
authors.lastname: Pang
authors.affiliation: First Municipal People's Hospital of Guangzhou, Guangdong Province, China.
authors.forename: Jiade
authors.initials: J
authors.lastname: Deng
authors.affiliation: Nanjing Clinical Nuclear Medical Centre, Nanjing Medical University Affiliated Nanjing First Hospital, Jiangsu Province, China.
authors.forename: Tongxin
authors.initials: T
authors.lastname: Du
authors.affiliation: People's Hospital of Peking University, Beijing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000378:metabolism*; D014508:Urea / Q000097:blood
chemical_list: D006442:Glycated Hemoglobin; D014508:Urea
keywords: Affinity chromatography; Carbamylated haemoglobin; HbA(1c); Ion-exchange chromatography