QDR 4500A DXA overestimates fat-free mass compared with criterion methods

Frances A Tylavsky, Timothy Lohman, Barbara A Blunt, Dale A Schoeller, Thomas Fuerst, Jane A Cauley, Michael C Nevitt, Marjolein Visser, Tamara B Harris

Research output: Contribution to JournalArticleAcademicpeer-review


This study evaluated the accuracy with which the dual-energy X-ray absorptiometer (Hologic QDR 4500A) measured fat-free mass (FFM), fat mass (FM), and hydration of FFM. In a study of 58 men and women (ages 70-79 yr), the QDR 4500A was found to provide a systematically higher estimate of FFM and lower estimate of FM than a four-component model of body composition. A correction factor from this study was developed and applied to two other samples (n = 13 and 37). We found mean corrected levels of FFM and FM to be equivalent to that obtained by the four-component model or total body water. In addition, the hydration of the corrected FFM was closer to the established hydration level in adult samples and that obtained from the four-component model. These findings suggest that the current calibration of the fan-beam system of the Hologic QDR 4500A provides an overestimate of FFM and underestimate of FM compared with reference methods.

Original languageEnglish
Pages (from-to)959-65
Number of pages7
JournalJournal of Applied Physiology (1985)
Issue number3
Publication statusPublished - Mar 2003


  • Absorptiometry, Photon
  • Aged
  • Aging
  • Algorithms
  • Body Composition
  • Body Mass Index
  • Calibration
  • Female
  • Humans
  • Male
  • Models, Biological
  • Reference Values
  • Clinical Trial
  • Journal Article
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.


Dive into the research topics of 'QDR 4500A DXA overestimates fat-free mass compared with criterion methods'. Together they form a unique fingerprint.

Cite this