PTH assays in dialysis patients: Practical considerations

Unlocking the mysteries of n-oxPTH: implications for CKD patients

Parathyroid hormone (PTH) is a pivotal hormone that regulates serum calcium and phosphate and is closely associated with higher risk of cardiovascular disease and mortality in patients with chronic kidney disease (CKD). PTH can undergo oxidation at methionine 8 and methionine 18 of the molecule. This oxidation process leads to a lower binding affinity to the PTH receptor due to molecular refolding, particularly for PTH oxidized at methionine 8. Although, the oxidation of PTH has been reported for several decades, it is only recently that a method has been developed to detect non-oxidized PTH (n-oxPTH) levels. The utilization of this assay enables the precise detection of n-oxPTH levels and facilitates the evaluation of their correlation with poor prognosis in patients with CKD. However, the current available clinical research findings indicate that n-oxPTH does not demonstrate clinical superiority over iPTH. Here, we provide a comprehensive review on the mechanism of PTH oxidation, the n-oxPTH assay method, and its correlation with iPTH and clinical outcomes.

The path to the standardization of PTH: Is this a realistic possibility? a position paper of the IFCC C-BM

Parathyroid hormone (PTH) determination is of greatest importance for patients suffering from parathyroid gland disorders and for the follow-up of bone turnover in patients suffering from chronic kidney disease (CKD). Two generations of PTH assays are simultaneously present on the market for PTH quantification. As these assays are not yet standardized, this results in a significant level of confusion in the care of CKD patients. One key objective of the IFCC Committee for Bone Metabolism is to improve this situation. In this position paper, we will highlight the current state of PTH testing and propose a pathway to ultimately overcome issues resulting from PTH assay variability.