Establishment of reference values in a healthy population and interpretation of serum PTH concentrations in hemodialyzed patients according to the KDIGO Guidelines using the Lumipulse® G whole PTH (3rd generation) assay

Background: 3rd generation PTH assays only detect the bioactive 1-84 fragment. Since standardization is still lacking, each new PTH assay requires to establish reference values and to assess the impact in the medical care of the mineral and bone disorders in hemodialyzed patients. Methods: Using Fujirebio Lumipulse G wPTH assay, serum PTH levels were measured in a population of 439 healthy subjects from France and Belgium PTH levels were also determined in 119 hemodialyzed patients. These patients were classified according to the KDIGO recommendation. Results: Reference range was found to be 6.5 (90% CI: 6.0-7.0) - 41.8 (90% CI: 38.1-43.7). In hemodialysis patients, Passing-Bablock regression between 3rd generation PTH from Fujirebio and DiaSorin was DiaSorin = 1.01 xFujirebio-2.4 with a slope not different from 1.0(95% CI: 0.96-1.04) and a non-significant intercept, ranging from -6.0 to 0.1. Hemodialysis patients with a PTH concentration below 2-fold the Upper Limit of Normality (ULN), within the KDIGO range and upper 9-fold upper limit were respectively 33.6%, 54.6%, 11.8% (Fujirebio Lumipulse) and 36.1%, 51.3% and 12.6% (Diasorin Liaison). Conclusion: We determined a reference range with the 3rd generation PTH assay from Fujirebio. In a hemodialysis population, 3rd generation assays from Fujirebio and DiaSorin provide similar results. To the best of our knowledge, this is the first time that we can show similar PTH results obtained by 2 different 3rd generation PTH assays in healthy subjects and hemodialyzed patients without mathematically processing them.