Although the whole PTH assay can measure almost exclusively full-length 1 to 84 PTH, its superiority over the intact PTH assay in predicting the diagnosis of renal osteodystrophy has not been established.50, 51, 52 Importantly, recent studies using high-resolution mass spectrometry have confirmed the absence of circulating 7 to 84 PTH,53 which was previously thought to accumulate in kidney failure and exert opposite effects of 1 to 84 PTH.54 Here, PTH is linked to kidney failure.