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Official Description

Oncology (ovarian), biochemical assays of five proteins (CA-125, apolipoprotein A1, beta-2 microglobulin, transferrin, and pre-albumin), utilizing serum, algorithm reported as a risk score

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 81503 pertains to a specific set of biochemical assays utilized in the field of oncology, particularly for evaluating the risk of ovarian cancer in women. This procedure involves the analysis of five distinct proteins: Cancer Antigen 125 (CA-125), apolipoprotein A1 (APO A1), beta-2 microglobulin, transferrin, and pre-albumin. These proteins are measured in serum obtained from a blood sample, which is collected through a separately reportable venipuncture. The results of these assays are then compiled into an algorithm that generates a risk score, providing valuable information regarding the likelihood of ovarian malignancy. The OVA1 assay, as indicated by this code, is specifically designed for women aged 18 years and older who present with an ovarian adnexal mass. This testing is particularly relevant when surgical intervention is being considered, and the patient has not yet been referred to an oncologist. The biochemical markers assessed in this test are critical for clinicians to make informed decisions regarding further diagnostic steps and potential treatment pathways. The methodology employed for testing includes quantitative electrochemiluminescent immunoassay for CA-125, quantitative nephelometry for APO A1, and quantitative immunoturbidimetry for the remaining proteins, ensuring accurate and reliable results that can guide clinical management.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The CPT® Code 81503 is indicated for use in women aged 18 years and older who present with an ovarian adnexal mass. This procedure is particularly relevant in the context of evaluating the risk for ovarian cancer, especially when surgical intervention is being planned and the patient has not yet been referred to an oncologist.

  • Ovarian Adnexal Mass The test is performed on women presenting with an ovarian adnexal mass to assess the risk of ovarian malignancy.
  • Pre-Surgical Evaluation It is utilized when surgery is planned, providing critical information before a referral to an oncologist.

2. Procedure

The procedure for CPT® Code 81503 involves several key steps to ensure accurate assessment of the biochemical markers associated with ovarian cancer risk. First, a blood sample is obtained from the patient through a separately reportable venipuncture. This step is crucial as it allows for the collection of serum, which is necessary for the subsequent testing. Once the blood sample is collected, the serum is subjected to various assays to measure the levels of the five specific proteins. Step 1: The serum is tested for Cancer Antigen 125 (CA-125) using a quantitative electrochemiluminescent immunoassay. This method is known for its sensitivity and specificity in detecting CA-125 levels, which are often elevated in ovarian cancer. Step 2: Next, apolipoprotein A1 (APO A1) is measured using quantitative nephelometry. This technique allows for the precise quantification of APO A1, which can provide additional context regarding the patient's risk profile. Step 3: The remaining proteins—beta-2 microglobulin, transferrin, and pre-albumin—are assessed using quantitative immunoturbidimetry. This method involves the formation of immune complexes that scatter light, allowing for the quantification of these proteins in the serum. After all assays are completed, the results are compiled into an algorithm that generates a risk score. This score is essential for clinicians to evaluate the likelihood of ovarian malignancy and to make informed decisions regarding further diagnostic and treatment options.

  • Step 1: Blood sample collection via venipuncture for serum analysis.
  • Step 2: Testing for CA-125 using quantitative electrochemiluminescent immunoassay.
  • Step 3: Measurement of APO A1 using quantitative nephelometry.
  • Step 4: Assessment of beta-2 microglobulin, transferrin, and pre-albumin using quantitative immunoturbidimetry.
  • Step 5: Compilation of results into an algorithm to generate a risk score for ovarian malignancy.

3. Post-Procedure

Post-procedure care following the administration of CPT® Code 81503 typically involves monitoring the patient for any immediate complications related to the venipuncture, such as bleeding or discomfort at the site of blood draw. Once the results of the biochemical assays are available, healthcare providers will review the risk score generated by the algorithm. This score is instrumental in guiding further clinical decisions, including the need for additional imaging studies, referrals to specialists, or surgical interventions. It is essential for the healthcare team to communicate the results effectively to the patient and discuss the implications of the findings in the context of their overall health and treatment options.

Short Descr ONCO (OVAR) FIVE PROTEINS
Medium Descr ONCO (OVARIAN) BIOCHEMICAL ASSAY FIVE PROTEINS
Long Descr Oncology (ovarian), biochemical assays of five proteins (CA-125, apolipoprotein A1, beta-2 microglobulin, transferrin, and pre-albumin), utilizing serum, algorithm reported as a risk score
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 Service Paid under Fee Schedule or Payment System other than OPPS
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T1H - Lab tests - other (non-Medicare fee schedule)
MUE 1
CCS Clinical Classification 234 - Pathology
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.
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
GZ Item or service expected to be denied as not reasonable and necessary
Date
Action
Notes
2017-01-01 Changed Guideline changed.
2014-01-01 Changed Code description changed.
2013-01-01 Added Added. Also, per AMA 2013 corrections document, corrected misspelling of "apolipoprotein".
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