Test Name: CANCER ANTIGEN (CA) 125
Test Code: 2120282
Alias: CA 125
CPT Code(s): 86304  
Test Includes: *This CPT code is subject to a Medicare Limited Coverage Policy and may require a signed ABN when ordering.

National Coverage Determination (NCD) for Tumor Antigen by Immunoassay - CA125:  https://www.cms.gov/medicare-coverage-database/details/ncd-details.aspx?NCDId=130&ncdver=2&bc=AAEAAAAAAAAA

Preferred Specimen: 1.0 mL serum
Container: SST (gold)
Alternate Container:

Lithium Heparin (lt green)


Minimum Volume: 0.3 mL serum or plasma
This volume does not allow for repeat testing.
Collection Instructions:

Allow specimen to completely clot (this can take up to 60 minutes). Centrifuge for 15 minutes. If the specimen is collected in a tube without a gel barrier, centrifuge and transfer the plasma into a properly labeled transfer tube within 2 hours of collection.

Transport Temperature: Refrigerated

Refrigerated: 5 days

Frozen: 3 months

Limitations: In patients receiving therapy with high biotin doses (i.e. > 5 mg/day), no sample should be taken until at least 8 hours after the last biotin administration.
Schedule: Set up: Daily; Results in 24-48 hours
Method: Electrochemiluminescence Immunoassay (ECLIA)
Clinical Significance: The CA 125 antigen may be found in elevated concentrations, in certain ovarian malignancies. There is no known function for CA 125. CA 125 antigen levels have no proven prognostic value when used for either screening or at time of diagnosis. However, CA 125 levels do correlate with patient status after initial treatment. CA 125 antigen levels may be used as an aid in monitoring the response to therapy for patients with epithelial ovarian carcinoma. The presence of persistently rising CA 125 antigen levels indicate poor response to therapy, whereas decreasing CA 125 antigen levels may indicate a positive therapeutic response.
Use: Updated 2/28/22

Reference Range Table

Result Units Gender Age Range
CA 125 units/mL Both 0 Year - 999 Year 0-35.0

The CPT codes included in this publication are in accordance with Current Procedural Terminology, a publication of the American Medical Association. CPT codes are provided here for the convenience of our clients; however, correct coding often varies from one carrier to another, and HealthLab may bill specific carriers using codes other than those shown. Clients who bill for services should verify the code(s) with the applicable payor to confirm that their use is appropriate in each case.

Test Type:



2635 Church Road, Suite 101|Aurora, IL 60502

Telephone: 630.315.6900|Fax: 630.315.6918

TTY: 711


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Open daily; closed on holidays

This location is part of Northwestern Medicine, and staff members are able to access electronic medical records.