This ELISA (enzyme-linked immunosorbent assay) kit is intended for measurement of both human osteocalcin (1-49) and osteocalcin (1-43) (also referred as N-terminal & mid-regional osteocalcin) levels in test samples. This test is useful for assessing the bone formation activity or osteoblast activity in individuals associated with changes in the rate of bone turnover in metabolic bone disease, such as osteoporosis, primary hyperparathyroidism, hyperthyroidism, Paget's disease, and renal osteodystrophy.