Among nondialysis CKD patients, diagnostic test characteristics of PTH, BSAP, P1NP, OCN, and TRAP‐5b for turnover type were similar to those reported for patients on dialysis.11, 12, 51, 52 Our investigation assessed diagnostic test characteristics for markers of CKD‐MBD [PTH, 25(OH)D, BSAP, FGF‐23], of bone formation (P1NP, OCN), and resorption (C‐telopeptide, TRAP‐5b) and of WNT signaling (SOST) for discrimination of ROD turnover type within the three bone compartments. The gene discussed is FGF23; the disease is Marchiafava-Bignami disease.