Validation of an adjusted calcium formula using the Roche calcium (NMBATPA) and albumin (BCG) methods at Groote Schuur Hospital

 

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dc.contributor.advisor Omar, Fierdoz en_ZA
dc.contributor.advisor Vreede, Helena en_ZA
dc.contributor.author Ndlovu, Mbali en_ZA
dc.date.accessioned 2017-09-26T14:47:50Z
dc.date.available 2017-09-26T14:47:50Z
dc.date.issued 2017 en_ZA
dc.identifier.citation Ndlovu, M. 2017. Validation of an adjusted calcium formula using the Roche calcium (NMBATPA) and albumin (BCG) methods at Groote Schuur Hospital. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/25381
dc.description.abstract ABSTRACT: Validation of an adjusted calcium formula using the Roche calcium (NMBATPA) and albumin (BCG) methods at Groote Schuur Hospital Introduction: Most laboratories continue to adjust serum total calcium (tCa) concentration for serum albumin as a surrogate marker of calcium status, despite the availability of ionised calcium (iCa) measurement. Current recommendations by the Association for Clinical Biochemistry and Laboratory Medicine (ACB) advocate that laboratories should use formulae specific for their tCa and albumin methods and analytical platforms. The National Health Laboratory Service at Groote Schuur Hospital (GSH) undertook to investigate this recommendation. An adjusted calcium (aCa) formula specific for the Roche serum tCa and albumin methods was derived from 3131 patients. We investigated the validity and clinical utility of this locally derived aCa formula. Methods: The tCa, albumin and iCa were analysed in blood from 162 inpatients and outpatients at GSH. Corrected calcium (cCa) was calculated using the Payne cCa formula, and aCa was calculated with the new aCa formula. Patients were classified as hypo-, normoor hypercalcaemic using iCa, tCa, cCa and aCa measurements. Cohen's kappa statistic, loglinear and logistic regression models and interclass and concordance correlation coefficients were used to assess agreement between tCa, Payne cCa and aCa against iCa (gold standard). Agreement was further assessed according to renal status and albumin concentrations. Results: The aCa demonstrated good correlation with iCa, but its performance was not significantly better than tCa or Payne cCa in correctly classifying calcium status. Furthermore, albumin concentration was demonstrated to predict the performance of the calcium status classification by the aCa and cCa formulae, irrespective of renal status. Conclusion: The laboratory-specific aCa formula did not perform significantly better than tCa and the Payne cCa formula. This implies that aCa does not add value over tCa where iCa measurements are not readily available. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Chemical Pathology en_ZA
dc.title Validation of an adjusted calcium formula using the Roche calcium (NMBATPA) and albumin (BCG) methods at Groote Schuur Hospital en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Health Sciences en_ZA
dc.publisher.department Division of Chemical Pathology en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MMed en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Ndlovu, M. (2017). <i>Validation of an adjusted calcium formula using the Roche calcium (NMBATPA) and albumin (BCG) methods at Groote Schuur Hospital</i>. (Thesis). University of Cape Town ,Faculty of Health Sciences ,Division of Chemical Pathology. Retrieved from http://hdl.handle.net/11427/25381 en_ZA
dc.identifier.chicagocitation Ndlovu, Mbali. <i>"Validation of an adjusted calcium formula using the Roche calcium (NMBATPA) and albumin (BCG) methods at Groote Schuur Hospital."</i> Thesis., University of Cape Town ,Faculty of Health Sciences ,Division of Chemical Pathology, 2017. http://hdl.handle.net/11427/25381 en_ZA
dc.identifier.vancouvercitation Ndlovu M. Validation of an adjusted calcium formula using the Roche calcium (NMBATPA) and albumin (BCG) methods at Groote Schuur Hospital. [Thesis]. University of Cape Town ,Faculty of Health Sciences ,Division of Chemical Pathology, 2017 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/25381 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Ndlovu, Mbali AB - ABSTRACT: Validation of an adjusted calcium formula using the Roche calcium (NMBATPA) and albumin (BCG) methods at Groote Schuur Hospital Introduction: Most laboratories continue to adjust serum total calcium (tCa) concentration for serum albumin as a surrogate marker of calcium status, despite the availability of ionised calcium (iCa) measurement. Current recommendations by the Association for Clinical Biochemistry and Laboratory Medicine (ACB) advocate that laboratories should use formulae specific for their tCa and albumin methods and analytical platforms. The National Health Laboratory Service at Groote Schuur Hospital (GSH) undertook to investigate this recommendation. An adjusted calcium (aCa) formula specific for the Roche serum tCa and albumin methods was derived from 3131 patients. We investigated the validity and clinical utility of this locally derived aCa formula. Methods: The tCa, albumin and iCa were analysed in blood from 162 inpatients and outpatients at GSH. Corrected calcium (cCa) was calculated using the Payne cCa formula, and aCa was calculated with the new aCa formula. Patients were classified as hypo-, normoor hypercalcaemic using iCa, tCa, cCa and aCa measurements. Cohen's kappa statistic, loglinear and logistic regression models and interclass and concordance correlation coefficients were used to assess agreement between tCa, Payne cCa and aCa against iCa (gold standard). Agreement was further assessed according to renal status and albumin concentrations. Results: The aCa demonstrated good correlation with iCa, but its performance was not significantly better than tCa or Payne cCa in correctly classifying calcium status. Furthermore, albumin concentration was demonstrated to predict the performance of the calcium status classification by the aCa and cCa formulae, irrespective of renal status. Conclusion: The laboratory-specific aCa formula did not perform significantly better than tCa and the Payne cCa formula. This implies that aCa does not add value over tCa where iCa measurements are not readily available. DA - 2017 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2017 T1 - Validation of an adjusted calcium formula using the Roche calcium (NMBATPA) and albumin (BCG) methods at Groote Schuur Hospital TI - Validation of an adjusted calcium formula using the Roche calcium (NMBATPA) and albumin (BCG) methods at Groote Schuur Hospital UR - http://hdl.handle.net/11427/25381 ER - en_ZA


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