TY - JOUR
T1 - Determination of fibroblast growth factor 23
AU - Heijboer, Annemieke C.
AU - Levitus, Marieke
AU - Vervloet, Marc G.
AU - Lips, Paul
AU - ter Wee, Piet M.
AU - Dijstelbloem, Hilde M.
AU - Blankenstein, Marinus A.
PY - 2009
Y1 - 2009
N2 - Background: Fibroblast growth factor 23 (FGF-23) is a recently discovered hormone, which plays a key role in phosphate regulation. To investigate whether FGF-23 can be determined reliably, we validated the three available FGF-23 assays. Methods: Currently, two intact FGF-23 assays (Kainos; Immutopics) and one C-terminal FGF-23 assay (Immutopics) are available. We determined intra- and inter-assay variation, linearity and matrix interference in these assays. Moreover, we compared assay results from healthy subjects with those of patient groups with expected high FGF-23 concentrations. Results: Intra-assay variation was reasonably good in all three assays. Inter-assay variation and linearity were poor for the intact Immutopics assay but reasonable for both other assays. Immutopics assays gave best results in ethylenediaminetetraacetic acid (EDTA) plasma, while the Kainos assay showed comparable reproducibility in EDTA plasma and serum. Although the manual of the Kainos assay states that an automatic washing machine can be used, acceptable results were only found by manual washing. Patients with kidney disease and patients with hypophosphatemic osteomalacia had increased C-terminal FGF-23 concentrations compared with healthy controls. Conclusion: Two assays of reasonable quality are available for FGF-23, the intact FGF-23 assay (Kainos) provided proper attention is paid to the washing procedure, and the C-terminal assay (Immutopics)
AB - Background: Fibroblast growth factor 23 (FGF-23) is a recently discovered hormone, which plays a key role in phosphate regulation. To investigate whether FGF-23 can be determined reliably, we validated the three available FGF-23 assays. Methods: Currently, two intact FGF-23 assays (Kainos; Immutopics) and one C-terminal FGF-23 assay (Immutopics) are available. We determined intra- and inter-assay variation, linearity and matrix interference in these assays. Moreover, we compared assay results from healthy subjects with those of patient groups with expected high FGF-23 concentrations. Results: Intra-assay variation was reasonably good in all three assays. Inter-assay variation and linearity were poor for the intact Immutopics assay but reasonable for both other assays. Immutopics assays gave best results in ethylenediaminetetraacetic acid (EDTA) plasma, while the Kainos assay showed comparable reproducibility in EDTA plasma and serum. Although the manual of the Kainos assay states that an automatic washing machine can be used, acceptable results were only found by manual washing. Patients with kidney disease and patients with hypophosphatemic osteomalacia had increased C-terminal FGF-23 concentrations compared with healthy controls. Conclusion: Two assays of reasonable quality are available for FGF-23, the intact FGF-23 assay (Kainos) provided proper attention is paid to the washing procedure, and the C-terminal assay (Immutopics)
U2 - https://doi.org/10.1258/acb.2009.009066
DO - https://doi.org/10.1258/acb.2009.009066
M3 - Article
C2 - 19564163
SN - 0004-5632
VL - 46
SP - 338
EP - 340
JO - Annals of clinical biochemistry
JF - Annals of clinical biochemistry
IS - Part 4
ER -