Parathyroid hormone control survey to determine inter-method and inter-lab variations in Japan.

For uremic patients, Kidney Disease: Improving Global Outcomes suggest that parathyroid hormone (PTH) levels should be maintained within approximately 2-9 times the upper normal limit for the assay. One of reasons for the lack of definite approximate PTH values is the inability to use the Allegro Intact PTH assay from Nicols. We aimed to evaluate whether other parathyroid hormone assays were suitable for these assessments. We compared the parathyroid hormone concentrations measured with five commercial immunoassays by using three serum pools and seven artificially spiked samples of parathyroid hormone; the Total Intact parathyroid hormone assay was used as the reference assay. Although the results of parathyroid hormone assays showed high correlation, the concentrations differed from Yamasa's assay to another. And the third/second-generation assay ratio was approximately 60%. Further, the Immulite assay overestimated the levels of 1-84 PTH. We showed important inter-method variations in the parathyroid hormone assays used in Japan.