Immunoradiometric assay for intact human osteocalcin(I-49) without cross-reactivity to breakdown products

John W. Colford, Bruce A. Lueddecke, Michael Salvati, Dave Hanna, Dawn Sailer, Sundeep Khosla, B. Lawrence Riggs, Craig B. Langman

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Background: Osteocalcin (Oc), a serum marker of bone turnover, circulates in several forms. We developed an assay for intact human Oc and investigated its clinical features. Methods: We generated goat antibodies and N- and C-terminal Oc. The former was used on solid phase (polystyrene beads), and the latter was used as the tracer in an IRMA. Results: The assay was linear with no Cross-reactivity to Oc(1,43), total imprecision (CV) of <10%, and recovery of 100% ± 10%. Assay values for intact Oc in EDTA plasma samples were unchanged at 18-25 °C for 6 h. Values for intact Oc in serum, EDTA plasma, and heparin plasma samples did not change after storage on ice for 8 h. Serum samples from patients with various conditions were stored at - 70 or -135 °C for up to 5 years and yielded z-scores comparable to an Oc(1- 43) IRMA for all conditions except for renal failure. In renal failure, the Oc(1-43) assay values were increased, whereas the intact assay values were in the reference interval. Conclusion: Decreases in Oc assay values are inhibited by calcium chelation, and slowed by reduced temperatures. The described assay for intact Oc allows improved specificity for bone compared with an assay for Oc(1-43).

Original languageEnglish (US)
Pages (from-to)526-531
Number of pages6
JournalClinical Chemistry
Volume45
Issue number4
StatePublished - 1999

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Immunoradiometric Assay
Osteocalcin
Assays
Plasmas
Edetic Acid
Renal Insufficiency
Bone
Bone Remodeling
Polystyrenes
Ice
Chelation
Serum
Goats
Heparin
Biomarkers

ASJC Scopus subject areas

  • Clinical Biochemistry

Cite this

Colford, J. W., Lueddecke, B. A., Salvati, M., Hanna, D., Sailer, D., Khosla, S., ... Langman, C. B. (1999). Immunoradiometric assay for intact human osteocalcin(I-49) without cross-reactivity to breakdown products. Clinical Chemistry, 45(4), 526-531.

Immunoradiometric assay for intact human osteocalcin(I-49) without cross-reactivity to breakdown products. / Colford, John W.; Lueddecke, Bruce A.; Salvati, Michael; Hanna, Dave; Sailer, Dawn; Khosla, Sundeep; Riggs, B. Lawrence; Langman, Craig B.

In: Clinical Chemistry, Vol. 45, No. 4, 1999, p. 526-531.

Research output: Contribution to journalArticle

Colford, JW, Lueddecke, BA, Salvati, M, Hanna, D, Sailer, D, Khosla, S, Riggs, BL & Langman, CB 1999, 'Immunoradiometric assay for intact human osteocalcin(I-49) without cross-reactivity to breakdown products', Clinical Chemistry, vol. 45, no. 4, pp. 526-531.
Colford, John W. ; Lueddecke, Bruce A. ; Salvati, Michael ; Hanna, Dave ; Sailer, Dawn ; Khosla, Sundeep ; Riggs, B. Lawrence ; Langman, Craig B. / Immunoradiometric assay for intact human osteocalcin(I-49) without cross-reactivity to breakdown products. In: Clinical Chemistry. 1999 ; Vol. 45, No. 4. pp. 526-531.
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