den Bakker E, Gemke R, Pottel H, van Wijk JAE, Hubeek I, Stoffel-Wagner B, Bökenkamp A. Estimation of GFR in children using rescaled beta-trace protein.
Clin Chim Acta 2018;
486:259-264. [PMID:
30121167 DOI:
10.1016/j.cca.2018.08.021]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/13/2018] [Accepted: 08/14/2018] [Indexed: 11/17/2022]
Abstract
INTRODUCTION
Beta-trace protein (BTP) is a low molecular weight protein, produced mainly in the cerebrospinal fluid. It has been proposed as a marker for kidney function. Recently, a new method for GFR estimation using mean normal values to rescale GFR marker concentrations has been described for creatinine and cystatin C, two commonly used endogenous markers for kidney function. The aim of this study is to apply this approach to BTP in children.
METHOD
We retrospectively analyzed serum concentrations of creatinine, cystatin C and BTP measured during inulin clearance tests in children. BTP was measured using a particle-enhanced immunonephelometric assay (Siemens Healthcare). A novel BTP-based eGFR equation was developed using published normal values for children: eGFRBTP[ml/min/1.73m2] = 107.3/BTP/QBTP with QBTP = 0.69. Performance of this equation was compared to the established creatinine-based full age spectrum equation FASage and the cystatin C-based FAScys equations as well as the BTP-based Benlamri equation in terms of bias, % prediction error and P30 and P10 accuracy rates.
RESULTS
322 inulin clearance tests were studied. Overall, our novel equation performed comparably to the creatinine-based FASage and the BTP-based Benlamri equations but was less accurate than FAScys (P30: 79.2 vs 86.3%, p = .008). Combining markers significantly enhanced performance compared to the single marker equations, with the exception of FAScys.
CONCLUSION
Rescaled BTP concentrations are a simple method for estimating GFR in children. However, the additional value of BTP for the estimation of GFR compared to rescaled creatinine and cystatin C still remains to be demonstrated.
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