Evaluation of Serum CTX and Osteocalcin Using Elecsys 2010

Jung, Tong Kil; Kim, Han Gil; Choi, Hyun Sik; Lee, Nan Young; Park, Sin Goo; Song, Kyung Eun

Abstract

BACKGROUND
In contrast with bone formation markers, most of available indices of bone resorption are urine markers and show relatively high degree of variability. The serum resorption assay has therefore been developed. We evaluated serum bone-derived degradation products of type I collagen C-telopeptide (s-CTX) and serum osteocalcin by Elecsys 2010 (Hitachi Boehringer Mannheim, Tokyo, Japan).
METHODS
For 18 healthy controls, 15 osteopenic and 7 osteoporotic patients samples, serum CTX and serum osteocalcin were measured by Elecsys 2010 using -CrossLaps/serum (Roche Diagnostic Corp., Indianapolis, USA) kit and N-MID Osteocalcin (Roche Diagnostic Corp. kit, respectively. DPD by Immulite (Diagnostic Products Corp., LA, USA) using Pyrilinks-D(TM) (Diagnostic Products Corp.) kit and serum osteocalcin for correlation by Gamma counter (Hewlett Packard, Meriden, USA) using ELSA-OSTEO (CIS, Cedex, France) kit were measured.
RESULTS
The within-run and between-run coefficient of variation (CV) values of s-CTX were 6.41% and 6% in low concentrations and 3.84% and 7% in high concentrations, respectively. The within-run and between-run CV values of serum osteocalcin were 2.21% and 6% in low concentrations and 1.25% and 3% in high concentrations, respectively. The dilution recovery of s-CTX and serum osteocalcin was 100-169% (mean, 134%) and 80-138% (mean, 104%), respectively. S-CTX and DPD (R=0.369, P=0.019), and serum osteocalcin by Elecsys 2010 and RIA (R=0.889, P<0.001) showed positive correlations, respectively. CONCLUSTIONS: S-CTX and serum osteocalcin by Elecsys 2010 exhibits good analytical performance and correlate with DPD and serum osteocalcin by RIA, respectively. Therefore, these may replace DPD and serum osteocalcin by RIA and can be used for bone resorption and formation markers, respectively.