Background/Aims: The introduction of capillary zone electrophoresis (CZE) to this laboratory has highlighted discrepancies in albumin measured on an Abbott Aeroset by bromocresol green ( BCG) and that calculated by CZE on the basis of total protein measured by Biuret. Methods: This study examined differences in albumin estimation by CZE, Abbott Aeroset BCG, and Aeroset bromocresol purple (BCP), and compared these with albumin estimated by Beckman Array immunoassay. Results: Altman and Bland analysis of results showed a positive bias of BCG with CZE (4.51 g/litre; 95% limits of agreement, 3.77 to 5.26; n = 72) and BCP (3.85 g/ litre; 95% limits of agreement, - 1.42 to 9.12; n = 72). CZE and BCP agreed closely (0.67 g/ litre; 95% limits of agreement, - 4.39 to 3.06; n = 72). Analysis of 57 of those samples in which BCG and CZE differed greater than or equal to 5 g/ litre showed a positive bias of BCG with immunoassay (8.35 g/ litre; 95% limits of agreement, 1.54 to 15.16; n = 57), with good agreement between CZE and immunoassay ( - 0.44 g/ litre; 95% limits of agreement, - 2.82 to 1.94; n = 57). Conclusions: BCP is superior to BCG for the assay of albumin and has replaced BCG as the routine test for albumin in this laboratory.
