The Kidney Disease: Improving Global Outcomes (KDIGO) have recently replaced the K/DOQI guidelines to help nephrologists in diagnosing, treating and monitoring chronic kidney disease mineral and bone disorders (CKD-MBD). Here, we comment on the KDIGO recommendations concerning the interpretation of parathyroid hormone (PTH) concentrations in dialysis patients: "In patients with CKD stage 5D, we suggest maintaining iPTH in the range of approximately two to nine times the upper normal limit of the assay. We suggest that marked changes in PTH concentrations in either direction within this range prompt an initiation or change in therapy to avoid progression to concentrations outside of this range". Our comments concern the interpretation of PTH in dialysis patients, but also the more global problem of establishing normal values for PTH.