This second-generation FDA-cleared parathyroid hormone (PTH) ELISA kit is a direct label 2-site ELISA intended for the quantitative determination of PTH in human plasma. The test offers a high-sensitivity (1 pg/mL) and simple 3-1/2-hour streptavidin-coated microplate assay procedure. The measurement of parathyroid hormone is the most specific way of making the diagnosis of primary hyperparathyroidism.