Second-generation assays have provided the basis for the Kidney Disease: Improving Global Outcomes (KDIGO) clinical guidelines on management of CKD-MBD.12,15 Significant inter-method variability among second-generation assays has been shown, thus affecting comparability of results.3 Taking this into consideration, the recent KDIGO guidelines proposed utilisation of multiples of 2–9-fold of the upper limit of normal for a given PTH assay, instead of absolute values in CKD patients on dialysis. The gene discussed is PTH; the disease is Marchiafava-Bignami disease.