Test Details: Osteocalcin is a protein hormone produced by osteoblasts, the cells that build bones. Osteocalcin binds calcium in the bones, working to maintain and regenerate bone tissue. The osteocalcin blood test is used for diagnosis of various bone diseases. Aids in diagnosis of medical conditions associated with increased bone turnover, including Paget disease, cancer accompanied by bone metastases, primary hyperparathyroidism, and renal osteodystrophy