title: The Interchangeability of Plasma and Whole Blood Metal Ion Measurement in the Monitoring of Metal on Metal Hips.
abstract: One hundred and twenty six paired samples of plasma and whole blood were measured with inductively coupled plasma mass spectrometry technique for metal ions analysis to determine a relationship between them. There was a significant difference between the mean plasma and whole blood concentrations of both cobalt (Co) and chromium (Cr) (p < 0.0001 for both Co and Cr). The mean ratio between plasma and whole blood Cr and Co was 1.56 (range: 0.39-3.85) and 1.54 (range: 0.64-18.26), respectively, but Bland and Altman analysis illustrated that this relationship was not universal throughout the range of concentrations. There was higher variability at high concentrations for both ions. We conclude that both these concentrations should not be used interchangeably and conversion factors are unreliable due to concentration dependent variability.
authors.affiliation: All Wales Orthopaedic Training Programme, Cardiff CF14 4XW, UK.
authors.forename: Ibrahim A
authors.initials: IA
authors.lastname: Malek
authors.affiliation: University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK.
authors.forename: Joanne
authors.initials: J
authors.lastname: Rogers
authors.affiliation: North Yorkshire Orthopaedic Training Programme, Huddersfield HD3 3EA, UK.
authors.forename: Amanda Christina
authors.initials: AC
authors.lastname: King
authors.affiliation: University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK.
authors.forename: Juliet
authors.initials: J
authors.lastname: Clutton
authors.affiliation: All Wales Orthopaedic Training Programme, Cardiff CF14 4XW, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Winson
authors.affiliation: University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK.
authors.forename: Alun
authors.initials: A
authors.lastname: John