Cancer Antigen 125

Test Code

CA125

Alias/See Also

Epic: LAB155

Preferred Specimen

Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 3 mL

Minimum Volume

1.0 mL

Instructions

Centrifuge and separate cells after clot formation and within 4 hours of collection

Transport Container

Plastic vial

Specimen Stability

Room temperature: Unacceptable
Refrigerated on gel: 24 hours
Refrigerated off gel: 7 days
Frozen: >7 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Specimens stored on gel >24 hours, gross hemolysis

Methodology

Chemiluminescent Micro-particle Immunoassay (CMIA)

Setup Schedule

Daily

Report Available

Same day

Limitations

Patients with Heterophile antibodies (HAMA) may exhibit falsely elevated or falsely depressed results.
CA 125 results should not be used interchangeably with other manufacturers’ methods for CA 125 determinations. Consistent tube type should be used to collect serial specimens.
CA 125 levels are not useful in screening the general population for cancer.
CA 125 levels should not be used alone as absolute evidence of the presence or absence of malignant disease. Clinical evaluation and other diagnostic procedures are needed.

Reference Range

<35.0 U/mL

Clinical Significance

CA 125 is a glycoprotein antigen present in tissues derived from ovarian, fallopian, peritoneal, colon, kidney, stomach, and other coelomic tissue. Increased levels are seen in patients with ovarian and intraperitoneal malignancy; the percentage of positive cases increasing with the cancer stage. CA 125 is also used to assess the effectiveness of ovarian/intraperitoneal cancer treatments and to predict recurrence and prognosis. Elevated levels of CA 125 may be seen in nonmalignant conditions, first trimester pregnancy, ovarian cysts, pelvic inflammatory disease, and during the menstrual cycle.

Performing Laboratory
Inova Laboratories
2832 Juniper Street
Fairfax, VA 22031

Last Updated: March 6, 2023
Last Review: N. Wolford, March 6, 2023

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.