PTH and Marchiafava-Bignami disease: Using this QSP model, we were able to describe the time course of the changes in serum concentrations of calcium (Ca), phosphorus (P), and parathyroid hormone (PTH), the three parameters routinely measured as part of clinical practice in the treatment of CKD-MBD as recommended by the Kidney Disease Improving Global Outcomes (KDIGO) guidelines (16).