The previously validated whole-molecule PTH immunoradiometric assay used by the laboratory since May 2010 has been discontinued by the manufacturer. Effective May 26, 2021, the MSU VDL will transition to a new automated intact PTH chemiluminescent immunometric assay. Serum remains the recommended sample type for the measurement of PTH.

This assay transition, and our recent transition for measurement of endogenous ACTH, also helps to reduce the amount of radioactive waste generated by the Laboratory. The transition for measurement of PTH impacts the following assays:

• Malignancy Profile (20030)
• Parathyroid Hormone and Ionized Calcium (20033)
• Vitamin D Profile (20035)

In pairwise analysis of canine, feline, and equine samples, results were highly correlated between the two techniques although the concentrations are numerically higher with the new assay. In a recovery study, pools of canine, feline, and equine samples with low, medium, and high concentrations of PTH yielded calculated mean recoveries of 97.3--109.1% in dilutional series. Reference ranges have been updated to reflect the change in assay.

Please refer to our online test catalog for the current and correct specimen type, collection protocol, shipping requirements, and additional information. Please contact us with any questions.