Clinical Evaluation of Bone Turnover by Serum Osteocalcin Measurements in a Hospital Setting*

Abstract

Serum levels of osteocalcin, the major noncollagenous bone protein, are elevated in patients with certain metabolic bone diseases, but the effects of other illnesses on serum osteocalcin levels are not known. We measured serum osteocalcin concentrations in 250 patients in a rehabilitation hospital who suffered from various illnesses. Mean serum osteocalcin levels were elevated in patients with 1) recent hip fracture who required open reduction and pin insertion (mean +/- SE, 19.0 +/- 3.2 ng/ml), 2) primary (22.0 +/- 4.9 ng/ml) or secondary hyperparathyroidism (51.6 +/- 9.9 ng/ml), 3) Paget's disease of bone (22.7 +/- 6.1 ng/ml), or 4) metastatic skeletal disease who had not received therapy (37.5 +/- 11.3). Mean serum osteocalcin levels were normal in patients who had received 1) a hip prosthesis for a recent fracture or for severe degenerative joint disease of the hip (6.4 +/- 0.9 ng/ml), 2) recent chemotherapy or irradiation for bone metastases (6.1 +/- 1.3 ng/ml), or 3) a variety of medical problems not related to bone disease (5.2 +/- 0.3 ng/ml). Serum osteocalcin and alkaline phosphatase values did not correlate. This study demonstrates that serum osteocalcin levels are normal in disorders not involving bone, can be used in a general-hospital setting, where concomitant illnesses are present, and may provide additional information for the clinical evaluation of metabolic bone disease.