ANALYTICAL PERFORMANCE AND CLINICAL USEFULNESS OF 2 BINDING ASSAYS FOR GROWTH-HORMONE BINDING-PROTEIN (GHBP) MEASUREMENT - HIGH-PERFORMANCELIQUID-CHROMATOGRAPHY (HPLC)-GEL FILTRATION AND DEXTRAN-COATED CHARCOAL ADSORPTION

We compared two binding assays for growth hormone binding protein (GHB P) measurements, which differ in the method of bound and free GH separ ation: HPLC-gel filtration or dextran coated-charcoal adsorption (DCC) . Two pools of sera (high and medium GHBP activity) were used for qual ity-control assessment. Moreover, 62 samples from 34 children and 28 a dults with different nutritional status were studied. Total, between-a nd intra-iodination coefficients of variation (CVs) from the two metho ds were not different. Although percentage binding measured in the poo l sera significantly differed, the concentrations assessed by Scatchar d plot were comparable. Results obtained by the two methods in the 62 sera were significantly correlated (r=0.77, P < 0.001). With both meth ods GHBP activity correlated with chronological age and body mass inde x (BMI) and differed among groups with different nutritional status. A lthough HPLC and DCC separation methods for GHBP measurement differ in their practicability, our study demonstrates that performance and the clinical usefulness of the two methods are comparable. (C) 1997 Elsev ier Science B.V.