Cancer Antigen 125 (CA-125) – Serum Probe Test
This test measures the level of CA-125, a protein sometimes produced by ovarian cancer cells and other conditions affecting the ovaries, fallopian tubes, or peritoneum.
["CA-125 levels may help detect or monitor certain cancers or related conditions."]
Key facts at a glance
- LOINC
- 95766-2
- Short code
- CAURDNA
- Synonyms
- C auris DNA Bld Ql NAA+n-prb
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (lavender-top) or ACD (yellow-top) blood collection tube; sterile transport container for blood culture bottles may also be acceptable
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- non-probe-amp-tar
- CPT
- 87798
- SNOMED
- 428531000124106
- Specimen volume
- 3-5 mL of whole blood; minimum 1 mL for pediatric patients
- Stability
- Ambient temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–72 hours
- Order
- routine
Why This Test Might Be Ordered
Your doctor may recommend this test if you have symptoms like pelvic pain, bloating, or irregular menstrual periods. It’s also used in follow-up for women with known ovarian cancer or other gynecologic conditions to check for recurrence or progression.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s drawn early in the morning. Bring any medications or supplements you’re taking to your appointment.
How the Test Is Performed
A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a brief pinch, but the procedure usually takes less than five minutes.
What the Results Mean
CA-125 results alone aren’t diagnostic for cancer—they’re part of a broader evaluation. Elevated levels may suggest ovarian cancer or other conditions, but further testing (like imaging or biopsy) would be needed to confirm.
Reference range
Not detected (Negative). Reference range applies to qualitative detection of Candida auris DNA in whole blood.N/A
No special patient preparation required. Standard aseptic venipuncture technique should be used to prevent specimen contamination. Specimen should be collected prior to initiation of antifungal therapy when clinically feasible. Follow institutional infection control protocols for patients suspected of C. auris colonization or infection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
CA-125 is a tumor marker used primarily in ovarian cancer screening, monitoring, and management. While it can indicate ovarian cancer, it’s not specific to it and may rise in other conditions like endometriosis, pelvic inflammatory disease, or benign ovarian cysts. Results should always be interpreted with clinical context and other diagnostic findings.
Short name
CA-125 Probe
Frequently asked questions
What does a CA-125 test measure?
Can a CA-125 test be used to diagnose ovarian cancer?
How often should I get a CA-125 test if I have a history of ovarian cancer?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy