Reference distributions for the negative acute-phase proteins, albumin, transferrin, and transthyretin: A comparison of a large cohort to the world'sliterature

Clinical interpretation of the acute-phase proteins-albumin, transferrin, a nd transthyretin-has been hampered by the lack of accurate and precise meth ods for quantifying the levels and a stable and respected reference materia l. Now that these issues have been addressed, the community is faced with t he need for credible age- and gender-specific reference values. The number of publications that address this issue, even for an analyte as familiar as albumin, is small and, in most cases, such publications lack the relevant data that would allow a combined experience to be created. We have identifi ed 40 studies that meet our criteria: a description of the study participan ts' health status, of the statistical methodology, and of the laboratory te chnique and/or reference material used. Few of these studies reported value s stratified by gender. A summary of the published median revels by age is presented for the three analytes, along with our own age- and gender-specif ic medians based on a large cohort. Ten of the studies presented a 95 perce nt reference range, in close agreement with ours where selection was based upon reported diagnosis rather than upon determination of individual health status. This meta-analysis provides support for the reliability of our rec ently published methodology and reference data for the clinical interpretat ion of individual albumin, transferrin, and transthyretin values. As with m ost laboratory measurements, clinical interpretation requires that other la boratory and clinical factors be considered. J. Clin. Lab. Anal. 13:280-286 , 1999. (C) 1999 Wiley-Liss, Inc.