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

doi:10.1093/clinchem/45.4.526

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

Endocrinology, Diabetes, Metabolism, and Nutrition

Research output: Contribution to journal › Article › peer-review

7 Scopus citations

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 language	English (US)
Pages (from-to)	526-531
Number of pages	6
Journal	Clinical chemistry
Volume	45
Issue number	4
DOIs	https://doi.org/10.1093/clinchem/45.4.526
State	Published - 1999

ASJC Scopus subject areas

Clinical Biochemistry
Biochemistry, medical

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

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).",

author = "Colford, {John W.} and Lueddecke, {Bruce A.} and Michael Salvati and Dave Hanna and Dawn Sailer and Sundeep Khosla and Riggs, {B. Lawrence} and Langman, {Craig B.}",

year = "1999",

doi = "10.1093/clinchem/45.4.526",

language = "English (US)",

volume = "45",

pages = "526--531",

journal = "Clinical chemistry",

issn = "0009-9147",

publisher = "American Association for Clinical Chemistry Inc.",

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TY - JOUR

T1 - Immunoradiometric assay for intact human osteocalcin(I-49) without cross-reactivity to breakdown products

AU - Colford, John W.

AU - Lueddecke, Bruce A.

AU - Salvati, Michael

AU - Hanna, Dave

AU - Sailer, Dawn

AU - Khosla, Sundeep

AU - Riggs, B. Lawrence

AU - Langman, Craig B.

PY - 1999

Y1 - 1999

N2 - 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).

AB - 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).

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

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