Diseases (10)

Overview

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.

Clinical Utility

  • As an aid in monitoring mineral and bone metabolism
  • Determine efficacy of therapy in osteoporosis and metastatic bone disease
  • Monitoring bone metabolic changes secondary to Cushing syndrome
  • Monitoring bone metabolic changes secondary to primary hyperparathyroidism
  • Monitoring bone metabolic changes secondary to malabsorption syndrome
  • As an aid in diagnosis of plasma cell myeloma
  • Selection of therapy for patients with hypercalciuria

Interpretation

Increased in:

  • Primary or secondary osteoporosis
  • Osteomalacia
  • Osteopenia due to vitamin D deficiency
  • Growth hormone deficiency
  • Hypogonadism
  • Paget’s disease
  • Osteoporosis
  • Cushing syndrome
  • Renal osteodystrophy
  • Inflammatory states such as rheumatoid arthritis
  • Bone metastasis
  • Hyperthyroidism
  • Primary Hyperparathyroidism
  • Myeloma
  • Hypercalciuria
  • Children
  • Long term corticosteroid use
  • Acromegaly
  • Recent bone fracture
  • Menopause
  • Lactation
  • Excercise
  • Incresed age

Decreased in:

  • Decreased results may indicate favorable therapeutic response
  • Pregnancy
  • Growth hormone deficiency
  • Hypothyroidism
  • Hypoparathyroidism
  • Liver disease
  • Alcoholism
  • Long term corticosteroid therapy
  • Obesity
  • Type 2 Diabetes

Reference Ranges

  ng/mL ug/L
Child 6-9.9 yr:  40.2-108  40.2-108
10-13.9 yr:  35.8-166  35.8-166
14-17.9 yr:    
M:  27.8-194  27.8-194
F:  16.3-68.7  16.3-68.7
Adult M:  11.3-35.4  11.3-35.4
F:  7.2-27.9  7.2-27.9
Adult M:  1.1-7.2  1.1-7.2
F, premenopausal:  0.5-7.0  0.5-7.0


 

 

Methodology

Enzyme Immunoassay (EIA), ELISA, RIA, IRMAs, ICMAs. Osteocalcin values vary widely between methods.

Specimen Collection

Serum

Serum Red top preferred, Serum gel(SST) acceptable.
Must be fasting.
Separate within 1 hr and freeze.

Additional Testing

Alkaline Phosphatase, Alkaline Phosphatase isoenzyme, Calcium Levels, Vitamin D, Parathyroid Hormone, Liver profile, Phosphorus.

Turnaround Time

1-3 days.

CPT

83937

ICD10

C41Malignant neoplasm of bone and articular cartilage of other and unspecified sites
C41.9Malignant neoplasm of bone and articular cartilage, unspecified
E05Thyrotoxicosis [hyperthyroidism]
E05.0Thyrotoxicosis with diffuse goiter
E05.1Thyrotoxicosis with toxic single thyroid nodule
E05.9Thyrotoxicosis, unspecified
E20Hypoparathyroidism
E20.8Other hypoparathyroidism
E20.9Hypoparathyroidism, unspecified
E21.0Primary hyperparathyroidism
E21.1Secondary hyperparathyroidism, not elsewhere classified
E21.2Other hyperparathyroidism
E21.3Hyperparathyroidism, unspecified
E28Ovarian dysfunction
E28.3Primary ovarian failure
E28.31Premature menopause
E28.310Symptomatic premature menopause
E28.39Other primary ovarian failure
E28.8Other ovarian dysfunction
E28.9Ovarian dysfunction, unspecified
E29Testicular dysfunction
E29.1Testicular hypofunction
E29.8Other testicular dysfunction
E29.9Testicular dysfunction, unspecified
E83Disorders of mineral metabolism
E83.39Other disorders of phosphorus metabolism
E83.41Hypermagnesemia
E83.42Hypomagnesemia
E83.49Other disorders of magnesium metabolism
E83.5Disorders of calcium metabolism
E89.4Postprocedural ovarian failure
M80.0Age-related osteoporosis with current pathological fracture
M81Osteoporosis without current pathological fracture
M85Other disorders of bone density and structure
M87Osteonecrosis
M87.10Osteonecrosis due to drugs, unspecified bone
M87.20Osteonecrosis due to previous trauma, unspecified bone
M87.30Other secondary osteonecrosis, unspecified bone
M87.8Other osteonecrosis
M87.80Other osteonecrosis, unspecified bone
M87.9Osteonecrosis, unspecified
M89Other disorders of bone
M90.50Osteonecrosis in diseases classified elsewhere, unspecified site
Q78.2Osteopetrosis
Z13.820Encounter for screening for osteoporosis
Z85Personal history of malignant neoplasm
Z85.83Personal history of malignant neoplasm of bone and soft tissue

References

  • JAMA. 2001; 285:785-95. [PMID:11176917]
  • Clin Calcium. 2009 Dec;19(12):1815-21. [PMID:19949273]
  • J Cell Biochem. 1995 Mar;57(3):379-83. [PMID:7768973]
  • Clin Orthop Relat Res. 1988 Jan;(226):267-91. [PMID:3275514]
  • Alan Wu. Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders; 4 edition (June 13, 2006). ISBN-10: 0721679757