PARATHYROID-HORMONE PART ..1. MEASUREMENT AND CLINICAL USE

The biochemistry, metabolism, and pathophysiology of parathyroid hormone (PTH) are sufficiently well understood to logically explain most clinical disorders involving parathyroid gland function and calcium metabolism. Early measurements of PTH used radioimmunoassays that detected various circulating fragments of PTH; these assays correlated poorly with one another and often gave results that conflicted clinically Now, with the advent of two-site immunometric PTH assays, analytical performance has been improved markedly and clinical discrimination among PTH disorders has been uniformly accurate. Recent advances in the measurement of PTH have focused on improving analytical sensitivity, building automated systems and providing rapid PTH results during surgical procedures on the parathyroid glands. This is the first article of a two-part series on PTH. The second part will describe our evaluation of two intact PTH assays and our implementation of one of these in our clinical service laboratory.