Comparison of two methods for the determination of ceruloplasmin in a pediatric hospital

Abstract

Introduction: Ceruloplasmin is an enzyme that uses copper as a cofactor. It can be determined in the laboratory by determining its enzymatic activity, which considers only the active portion, or by measuring its protein concentration, which considers both the active and inactive portion. Ceruloplasmin is useful in diagnosing Wilson’s and Menkes’ diseases, in which it is found mainly as an inactive form due to low circulating copper. This means that methods that measure concentration can overestimate it and lose diagnostic sensitivity. Objective: To evaluate the correlation and concordance between an enzymatic method and an immunoturbidimetric method to measure Ceruloplasmin. Materials and methods: An analytical observational study was carried out to compare the enzymatic method of Henry et al. and the CERU® immunoturbidimetric method (Roche, Cobas c311) for the determination of Ceruloplasmin, using serum samples from pediatric patients, with medical request for this determination, in the period April 2018 - March 2021. The statistical analysis performed (IBM SPSS Statistics version 21) consisted of a correlation study (Pearson) and a concordance study (Bland Altman). Results: 51 samples were analyzed, obtaining r=0.916 in the Pearson correlation (p<0.0001) and a Bland Altman graph with positive bias. Conclusion: A good correlation was found, although the concordance analysis showed a positive bias. Since the agreement is good in the medical decision area, it is concluded that both methodologies can be interchangeable.