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Official Description

Osteocalcin (bone g1a protein)

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 83937 refers to the measurement of osteocalcin, which is a non-collagen protein produced by osteoblasts, the cells responsible for bone formation. This blood test is significant as it serves as a biomarker for bone turnover, providing valuable insights into the metabolic processes of bone health. Osteocalcin levels can be indicative of various conditions affecting bone density and strength, making it a useful tool in monitoring the effectiveness of therapeutic interventions in patients diagnosed with osteopenia or osteoporosis. Elevated levels of osteocalcin may be observed in several pathological conditions, including Paget's disease, bone cancer, fractures, acromegaly, primary hyperparathyroidism, hyperthyroidism, and renal osteodystrophy. Conversely, decreased levels of osteocalcin can occur in cases of hypoparathyroidism, hypothyroidism, and deficiencies in growth hormone. The test is performed by obtaining a blood sample through venipuncture, which is a separately reportable procedure. The serum or plasma obtained from the blood sample is then analyzed using a quantitative electrochemiluminescent immunoassay, a sensitive and specific method for measuring the concentration of osteocalcin in the blood.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The osteocalcin test (CPT® Code 83937) is indicated for various clinical scenarios where monitoring bone metabolism is essential. The following conditions may warrant the performance of this test:

  • Osteopenia/Osteoporosis - To assess bone turnover and monitor the effectiveness of drug therapy aimed at improving bone density.
  • Paget's Disease - To evaluate bone remodeling activity in patients diagnosed with this condition.
  • Bone Cancer - To monitor changes in bone metabolism associated with malignancies affecting bone tissue.
  • Fractures - To assess the healing process and bone turnover following a fracture.
  • Acromegaly - To evaluate the impact of excess growth hormone on bone metabolism.
  • Primary Hyperparathyroidism - To assess bone turnover in patients with elevated parathyroid hormone levels.
  • Hyperthyroidism - To evaluate the effects of increased thyroid hormone levels on bone metabolism.
  • Renal Osteodystrophy - To monitor bone health in patients with chronic kidney disease.
  • Hypoparathyroidism - To assess decreased osteocalcin levels in patients with low parathyroid hormone levels.
  • Hypothyroidism - To evaluate the impact of low thyroid hormone levels on bone metabolism.
  • Growth Hormone Deficiency - To assess the effects of growth hormone deficiency on bone health.

2. Procedure

The procedure for measuring osteocalcin levels involves several key steps to ensure accurate results. First, a qualified healthcare professional will perform a venipuncture, which is the process of inserting a needle into a vein to obtain a blood sample. This step is crucial as it provides the serum or plasma needed for the test. The blood sample is then collected into a suitable container, typically a serum separator tube, to facilitate the separation of serum from the cellular components of the blood. Once the blood is drawn, it is processed in a laboratory setting where the serum or plasma is isolated. The next step involves the application of a quantitative electrochemiluminescent immunoassay, a sophisticated testing method that utilizes specific antibodies to detect and quantify the levels of osteocalcin in the sample. This assay is known for its sensitivity and specificity, allowing for precise measurement of osteocalcin concentrations. The results of the test are then analyzed and reported, providing valuable information regarding the patient's bone metabolism and potential underlying conditions.

3. Post-Procedure

After the blood sample has been collected for the osteocalcin test, there are generally no specific post-procedure care requirements for the patient. However, it is advisable for patients to remain hydrated and to follow any additional instructions provided by the healthcare professional. The results of the osteocalcin test will typically be available within a few days, and healthcare providers will discuss the findings with the patient during a follow-up appointment. It is important for patients to understand the implications of their test results, especially in relation to their bone health and any ongoing treatment plans. If elevated or decreased levels of osteocalcin are detected, further evaluation or adjustments to treatment may be necessary based on the clinical context and the patient's overall health status.

Short Descr ASSAY OF OSTEOCALCIN
Medium Descr ASSAY OF OSTEOCALCIN
Long Descr Osteocalcin (bone g1a protein)
Status Code Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 9 - Not Applicable
Multiple Procedures (51) 9 - Concept does not apply.
Bilateral Surgery (50) 9 - Concept does not apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 9 - Concept does not apply.
Co-Surgeons (62) 9 - Concept does not apply.
Team Surgery (66) 9 - Concept does not apply.
Diagnostic Imaging Family 99 - Concept Does Not Apply
CLIA Waived (QW) No
APC Status Indicator Conditionally packaged laboratory tests
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T1H - Lab tests - other (non-Medicare fee schedule)
MUE 1
CCS Clinical Classification 233 - Laboratory - Chemistry and Hematology
90 Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.
77 Repeat procedure by another physician or other qualified health care professional: it may be necessary to indicate that a basic procedure or service was repeated by another physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 77 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
GA Waiver of liability statement issued as required by payer policy, individual case
GW Service not related to the hospice patient's terminal condition
GY Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit
Q4 Service for ordering/referring physician qualifies as a service exemption
Date
Action
Notes
2013-01-01 Changed Medium Descriptor changed.
1994-01-01 Added First appearance in code book in 1994.
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