The up-to-date of PTH assay: the progression and some clinical problem

Abstract

Intact-PTH assay measures not only (1-84) -PTH [biological active form] but also (7-84) -PTH as a C-terminal PTH fragment with competitive inhibitory effect in end stage renal disease (ESRD) patients. This weak point of intact-PTH assay is an explanation of skeletal resistance with over-estimation of parathyroid function in ESRD patients. Recently, the new PTH assay named "whole PTH assay" was developed. This new assay can measure the only full-length biological active form (1-84) -PTH without the cross-link of C-terminal PTH fragments. The result of whole PTH assay was low such as 43% in HD patients, 42% in CAPD patients, 30% in pre-dialysis renal failure patients, and 24% in kidney transplantation patients, compared with the results of intact-PTH assay. The difference between whole PTH assay and intact-PTH assay was mainly influenced by residual renal function but not dialysis modality.