Osteocalcin is the major non-collagen calcium binding protein and it is excreted by osteoblasts in the bone. The serum concentrations are an indication of bone formation. The synthesis of osteocalcin is vitamin D independent. Elevated results are usually associated with increased bone turnover such as what is seen in osteoporosis. Bisphosphonated drugs used to treat osteoporosis can be monitored for effectiveness by measuring osteocalcin levels. Levels are normally high in childhood and then peak in early puberty. During menopause a second peak usually occurs in females.
Although results are not strictly diagnostic of osteoporosis, a decrease in the value can be interpreted as evidence of a favorable response to treatment. Patients that are on vitamin K antagonist medication can have unreliable results. Therefore, ELISA methodology is the best choice to test for undercarboxylated osteocalcin. This assay should be used in conjunction with other bone markers for best interpretation. Bone mineral densitometry and imaging studies are the gold standard for the evaluation of osteoporosis. Bone formation/ resorption may be accurately reflected in patients taking 1,25-dihydroxyvitamin D or if there is an abnormality with it.
Of note, bone formation and serum Osteocalcin level follows a diurnal rhythm and is also subject to the menstrual cycle. Variation by as much as 50% can be seen from a nocturnal peak to a morning low, with a 10% day to day variation, and as large as a 60% increase can be seen following a fracture.
|Child 6-9.9 yr:||40.2-108||40.2-108|
Enzyme Immunoassay (EIA), ELISA, RIA, IRMAs, ICMAs. Osteocalcin values vary widely between methods.
Serum Red top preferred, Serum gel(SST) acceptable.
Must be fasting.
Separate within 1 hr and freeze.
Alkaline Phosphatase, Alkaline Phosphatase isoenzyme, Calcium Levels, Vitamin D, Parathyroid Hormone, Liver profile, Phosphorus.
|C41||Malignant neoplasm of bone and articular cartilage of other and unspecified sites|
|C41.9||Malignant neoplasm of bone and articular cartilage, unspecified|
|E05.0||Thyrotoxicosis with diffuse goiter|
|E05.1||Thyrotoxicosis with toxic single thyroid nodule|
|E21.1||Secondary hyperparathyroidism, not elsewhere classified|
|E28.3||Primary ovarian failure|
|E28.310||Symptomatic premature menopause|
|E28.39||Other primary ovarian failure|
|E28.8||Other ovarian dysfunction|
|E28.9||Ovarian dysfunction, unspecified|
|E29.8||Other testicular dysfunction|
|E29.9||Testicular dysfunction, unspecified|
|E83||Disorders of mineral metabolism|
|E83.39||Other disorders of phosphorus metabolism|
|E83.49||Other disorders of magnesium metabolism|
|E83.5||Disorders of calcium metabolism|
|E89.4||Postprocedural ovarian failure|
|M80.0||Age-related osteoporosis with current pathological fracture|
|M81||Osteoporosis without current pathological fracture|
|M85||Other disorders of bone density and structure|
|M87.10||Osteonecrosis due to drugs, unspecified bone|
|M87.20||Osteonecrosis due to previous trauma, unspecified bone|
|M87.30||Other secondary osteonecrosis, unspecified bone|
|M87.80||Other osteonecrosis, unspecified bone|
|M89||Other disorders of bone|
|M90.50||Osteonecrosis in diseases classified elsewhere, unspecified site|
|Z13.820||Encounter for screening for osteoporosis|
|Z85||Personal history of malignant neoplasm|
|Z85.83||Personal history of malignant neoplasm of bone and soft tissue|