PTH and Marchiafava-Bignami disease: However, it is invasive, expensive, and requires expertise not readily available, thus measurement of circulating biomarkers, including parathyroid hormone (PTH), offers an attractive non-invasive alternative.1,3 Changes in PTH concentrations contribute to the bone abnormalities observed in CKD-MBD.4 This makes its measurement essential in the management of CKD-MBD.