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HelpTest ID: CA25 Cancer Antigen 125 (CA 125), Serum
Reporting Name
Cancer Ag 125 (CA 125), SUseful For
Evaluating individuals' response to ovarian cancer therapy
Predicting recurrent ovarian cancer
This test is not useful for cancer detection screening in the normal population.
Clinical Information
Cancer antigen 125 (CA 125) is a glycoprotein antigen normally expressed in tissues derived from coelomic epithelia (ovary, fallopian tube, peritoneum, pleura, pericardium, colon, kidney, stomach).
Serum CA 125 is elevated in approximately 80% of women with advanced epithelial ovarian cancer, but the assay sensitivity is suboptimal in early disease stages. The average reported sensitivities are 50% for stage I and 90% for stage II or greater.
Elevated serum CA 125 levels have been reported in individuals with a variety of nonovarian malignancies including cervical, liver, pancreatic, lung, colon, stomach, biliary tract, uterine, fallopian tube, breast, and endometrial carcinomas.
Elevated serum CA 125 levels have been reported in individuals with a variety of benign conditions including: cirrhosis, hepatitis, endometriosis, first trimester pregnancy, ovarian cysts, and pelvic inflammatory disease. Elevated levels during the menstrual cycle also have been reported.
Interpretation
In monitoring studies, elevations of cancer antigen 125 (CA 125) above the reference interval after debulking surgery and chemotherapy indicate that residual disease is likely (>95% accuracy). However, normal levels do not rule out recurrence.
A persistently rising CA 125 value suggests progressive malignant disease and poor therapeutic response.
Physiologic half-life of CA 125 is approximately 5 days.
In individuals with advanced disease who have undergone cytoreductive surgery and are on chemotherapy, a prolonged half-life (>20 days) may be associated with a shortened disease-free survival.
Report Available
1 to 3 daysDay(s) Performed
Monday through Friday
Clinical Reference
1. Zhang M, Cheng S, Jin Y, Zhao Y, Wang Y. Roles of CA125 in diagnosis, prediction, and oncogenesis of ovarian cancer. Biochim Biophys Acta Rev Cancer. 2021;1875(2):188503. doi: 10.1016/j.bbcan.2021.188503
2. Charkhchi P, Cybulski C, Gronwald J, Wong FO, Narod SA, Akbari MR. CA125 and Ovarian Cancer: A Comprehensive Review. Cancers (Basel). 2020;12(12):3730. doi: 10.3390/cancers12123730. PMID: 33322519; PMCID: PMC7763876
3. Sturgeon CM, Duffy MJ, Stenman UH, et al. National Academy of Clinical Biochemistry laboratory medicine practice guidelines for use of tumor markers in testicular, prostate colorectal, breast, and ovarian cancers. Clin Chem. 2008;54(12):11-79
4. The Role of the Obstetrician-Gynecologist in the Early Detection of Epithelial Ovarian Cancer. American College of Obstetricians and Gynecologists. 2011. Committee Opinion Number 477
Method Name
Electrochemiluminescent Immunoassay (ECLIA)
Specimen Type
SerumSpecimen Required
Patient Preparation: For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial.
Specimen Minimum Volume
0.75 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 5 days | |
| Frozen | 168 days |
Reference Values
Males: Not applicable
Females: <46 U/mL
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
86304
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CA25 | Cancer Ag 125 (CA 125), S | 83082-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CA25 | Cancer Ag 125 (CA 125), S | 83082-8 |
Forms
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.
mml-Neuroimmunology, mml-Neuro-oncology, mml-Pediatric