Qing Li1, Yi Ju2, Ting Jin3, Biqiong Pang3, Jiade Deng4, Tongxin Du5, Hong Wang6. 1. Shanghai Centre for Clinical Laboratory, Shanghai, China. 2. Shanghai Centre for Clinical Laboratory, Shanghai, China. Electronic address: juyi@sccl.org.cn. 3. First Hospital of Fuzhou, Fujian Province, China. 4. First Municipal People's Hospital of Guangzhou, Guangdong Province, China. 5. Nanjing Clinical Nuclear Medical Centre, Nanjing Medical University Affiliated Nanjing First Hospital, Jiangsu Province, China. 6. People's Hospital of Peking University, Beijing, China.
Abstract
OBJECTIVES: 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. DESIGN AND 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. CONCLUSION: HbA1c measurement by these methods may not be impacted by carbamylated Hb. The results should be interpreted with caution in high carbamylated Hb patients.
OBJECTIVES: 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. DESIGN AND 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 CKDpatients were diagnosed. The average HbA₁c and urea levels of nondiabetic and diabeticpatients 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. CONCLUSION: HbA1c measurement by these methods may not be impacted by carbamylated Hb. The results should be interpreted with caution in high carbamylated Hb patients.