PTH and Marchiafava-Bignami disease: In fact, according to current guidelines, the measurement of both serum PTH and bone AP can be used to evaluate bone disease in CKD patients because markedly high or low values predict underlying bone turnover (Kidney Disease: Improving Global Outcomes KDIGO CKD-MBD Update Work Group, 2017; Jørgensen et al., 2022a).