The differences between the serum albumin determined by bromocresol green (BCG) and immunonephelometry (IN) were inconsistent in past studies, and the samples were all adults. We sought to determine the differences in children and reveal the impacts of these differences on the clinical diagnosis and treatments of primary nephrotic syndrome (PNS). Repeated measurements from 576 PNS children showed that albumin measured by BCG and IN (ALB-B and ALB-I) were 19.95 (11.15) g/L and 15.30 (11.05) g/L, respectively, and the mean difference was 4.68 g/L (P < 0.001). The cut-offs we calculated for hypoalbuminemia and severe hypoalbuminemia based on the IN were 25 and 15 g/L, which were 5 g/L lower than the cut-offs recommended by KIDGO, respectively. A pair of historical control samples (206 vs. 216) with ALB-B or ALB-I showed that the proportion of severe hypoalbuminemia was 14.60% greater in IN group (75.20% vs. 60.60%, P < 0.001). The misdiagnosis rate of severe hypoalbuminemia by IN was 33.77% when 20 g/L rather than 15 g/L was used as the cut-off. Furthermore, the proportion of patients receiving albumin injections increased by 10.20%, and the average consumption increased by 97.06% (P = 0.01) along with the use of IN. So, our results suggested that the difference between ALB-B and ALB-I led to misdiagnosis and prescription abuse in PNS children.

The different serum albumin assays influence the prescriptions in children with primary nephrotic syndrome