Letters Section Editor: Stephen J. Lurie, MD, PhD, Senior Editor.
In Reply: The assay for soluble free RANKL
has been validated according to usual standards,1 is
commercially available, and is commonly used.1- 3 Main
characteristics including lower detection limit and interassay as well as
intra-assay coefficients of variation are provided.1,4 Mean
serum levels of RANKL are very similar among different cohorts.1,4 RANKL
levels emerged as stable over a 5-year period and correlations between RANKL
levels measured from 1990 and 1995 blood samples and between 1990 and 2000
were high, at 0.63 and 0.36 pmol/L, respectively. Figure 2 in our study was
based on all individuals.
Schett G, Redlich K, Pietschmann P, Smolen J, Kiechl S, Willeit J, Oberhollenzer F, Weger S, Egger G, Mayr A, Jocher J, Xu Q, Teitelbaum S. Soluble RANKL and Risk of Nontraumatic Fracture—Reply. JAMA. 2004;291(22):2703. doi:10.1001/jama.291.22.2703-b