Universal standardization of bone density measurements: A method with optimal properties for calibration among several instruments

Siu L. Hui, Sujuan Gao, Xiao Hua Zhou, C. Conrad Johnston, Ying Lu, Claus C. Glüer, Stephen Grampp, Harry Genant

Research output: Contribution to journalArticle

170 Scopus citations


The International Dual-Photon X-Ray Absorptiometry (DXA) Standardization Committee (IDSC) conducted a cross-calibration study among three models of DXA machines from three different manufacturers. In that study, 100 subjects were scanned on all three machines. A set of equations were derived to convert bone mineral density (BMD) on each machine to a 'standardized BMD' (sBMD) such that sBMD from the same subject derived from different machines would be approximately the same. In a reanalysis of the cross-calibration data, we showed that the conversion method used in the IDSC study did not achieve several optimal properties desirable in such conversions. We derived new conversion equations to sBMD based on minimizing differences among sBMD from the three machines. More important is that the new conversions have no residual bias that was present in the IDSC conversions. The performance of the methods were compared on the cross-calibration data as well as an external data set. We conclude that the IDSC conversions are adequate for clinical use on other machines worldwide, but that researchers should standardize their own machines in a laboratory using the new method.

Original languageEnglish (US)
Pages (from-to)1463-1470
Number of pages8
JournalJournal of Bone and Mineral Research
Issue number9
StatePublished - Sep 1 1997


ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Orthopedics and Sports Medicine

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