Comparison of seven different enzymatic methods for serum glycated albumin in pregnant women: a multicenter study.

Objectives: To evaluate the consistency of seven enzymatic glycated albumin (GA) assays in pregnant women based on a multicenter study.

Methods: Samples were collected from pregnant women at three different gestational stages: 4-13 weeks (n=150), 24-28 weeks (n=300, including 150 GDM subjects), and 29-40 weeks (n=300, including 150 GDM subjects), across three hospitals between July 2022 and December 2023 in China. These samples were analyzed using seven enzymatic GA methods (Lucica, Norudia, BSBE, Maccura, Meikang, Reebio, and Zybio assays). Spearman correlation analysis, Passing-Bablok regression, and Bland-Altman plots were used to evaluate the consistency between the Lucica used in our laboratory and the other selected assays. The effects of albumin concentration and gestational stage on the consistency of GA were evaluated through stratified analyses.

Results: The correlation coefficients between Lucica and the other six assays for GA% measurement ranged from 0.741 to 0.906 (p<0.0001), with the mean relative biases ranging from -15.5 to +6.7 %. In trimester-stratified analysis, the highest correlation coefficient was observed in the first trimester for all assays except Maccura, and the bias increased with advancing gestational age for all assays except BSBE. In albumin-stratified analysis (30-45 g/L), the correlation increased with increasing albumin concentration for all assays, while the bias decreased except for BSBE and Maccura assays.

Conclusions: Poor analytical consistency was observed in enzymatic GA assays for pregnant women, with discrepancies varying across gestational stages and albumin concentrations. Reference intervals for pregnant women should be established based on trimester-stratified and manufacturer-specific criteria.