Qualitative and quantitative comparison of different commercially available 1-84 parathyroid hormone proteins to the WHO international standard 95/646 using orthogonal methods

Relative quantitation methods rely on the use of reference substances to determine the content of samples. The aim of this study was to compare 1-84 parathyroid hormone (PTH) standards from different manufacturers to the WHO international standard 95/646. CE and LC with UV detection were investigated as quick and inexpensive quantitation methods, with an emphasis on selectivity between intact 1-84 PTH and its oxidized forms. Both methods were fully validated according to ICH Q2R1. Moreover, method performance was also evaluated ac-cording to guidelines defining the maximum allowable measurement uncertainty (MU) of a biological parameter from its intraindividual variation (CVI), as well as the proportion of that MU devoted to the reference material. This study highlighted the fact that some 1-84 PTH standards have a content that is actually twice as high as the one stated on the label, which was confirmed by an amino acid analysis investigation. Our approach offers a quick and inexpensive way to estimate the content of 1-84 PTH standards.

Automated summary

The study aimed to compare 1-84 parathyroid hormone (PTH) standards from different manufacturers to the WHO international standard, while investigating CE and LC methods as quick and inexpensive quantitation methods. The research also revealed that some 1-84 PTH standards have content twice as high as indicated on the label.