Quick Facts
- Sample: Blood draw (serum)
- Fasting: No fasting required
- Turn-around: 1–2 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Monitor ovarian cancer treatment - Track therapy effectiveness and detect recurrence early
- Screen high-risk women - Evaluate those with family history or genetic predispositions
- No doctor visit required - Direct access eliminates appointment delays and referral costs
- Quick, simple blood test - Minimal preparation with results in 1-2 days
- Confidential results - Secure online delivery maintains complete privacy
- Cost-effective monitoring - Affordable surveillance for ongoing cancer survivors
Who Is This Test For?
- Women with family history of ovarian or breast cancer
- Those with BRCA mutations or Lynch syndrome genetic markers
- Cancer survivors monitoring for potential recurrence
- Women experiencing persistent pelvic symptoms like bloating or pain
- Those with endometriosis requiring biomarker tracking
- High-risk individuals seeking proactive health management
How It Works – Just 3 Steps
- Order online - No appointment needed, schedule at your convenience
- Visit lab - Quick blood draw at 5,000+ locations nationwide
- Get results - Secure online delivery with physician interpretation within 1-2 days
FAQ
What does CA-125 measure? CA-125 is a protein biomarker that can be elevated in ovarian cancer and other conditions affecting the reproductive organs.
Is this test accurate for early ovarian cancer detection? CA-125 detects 85% of advanced ovarian cancers but only 50% of early-stage cases, requiring clinical correlation for interpretation.
Can other conditions cause elevated CA-125? Yes, benign conditions like menstruation, endometriosis, and pelvic inflammation can also raise CA-125 levels.
Do I need to stop any medications before testing? Discontinue biotin supplements 72 hours before testing, as they can interfere with results accuracy.
How often should cancer survivors get tested? Most oncologists recommend CA-125 monitoring every 3-6 months for the first few years after treatment.
What if my results are elevated? Elevated levels require follow-up with imaging studies and clinical evaluation to determine the underlying cause.
More Details
What is the purpose of this test?
The CA-125 serum test measures cancer antigen 125, a glycoprotein produced by cells lining the ovaries, uterus, and peritoneum (Mayo Clinic 2025). This blood-based biomarker serves multiple clinical purposes in women's health management.
Primary applications include monitoring ovarian cancer treatment response, detecting cancer recurrence in survivors, and evaluating suspicious pelvic masses when combined with imaging studies (Cleveland Clinic 2025). The test also supports endometriosis diagnosis and helps assess inflammatory pelvic conditions.
While CA-125 elevation occurs in approximately 85% of advanced ovarian cancer cases, it's important to understand that elevated levels can also result from benign conditions including menstruation, endometriosis, and pelvic inflammatory disease (Johns Hopkins 2020).
Who would benefit from this test?
Women with family histories of ovarian or breast cancer represent the primary beneficiary group, particularly those with BRCA1 or BRCA2 genetic mutations (CDC 2024). These individuals face significantly elevated lifetime cancer risks requiring proactive monitoring strategies.
Cancer survivors benefit tremendously from regular CA-125 surveillance, as serial testing can detect recurrence months before symptoms appear (NCCN 2024). This early detection capability often translates to improved treatment outcomes and survival rates.
Women experiencing persistent pelvic symptoms including bloating, abdominal pain, difficulty eating, or urinary urgency should consider CA-125 testing as part of comprehensive evaluation. Additionally, those with diagnosed endometriosis may benefit from monitoring to track disease progression and treatment response.
Healthcare-conscious individuals seeking preventive insights can establish personal baseline values through serial testing, particularly valuable for those with Lynch syndrome or other hereditary cancer predispositions.
When should I order a Cancer Antigen (CA) 125 Serum Test?
Consider ordering CA-125 testing when experiencing persistent pelvic symptoms lasting more than two weeks, including abdominal bloating, pelvic pain, difficulty eating, or changes in urinary patterns (American Cancer Society 2025).
High-risk screening is appropriate for women with strong family histories of ovarian or breast cancer, particularly those with known BRCA mutations or Lynch syndrome. Genetic counselors often recommend baseline testing followed by regular monitoring intervals.
Post-treatment surveillance represents another critical indication, with most oncologists recommending testing every 3-6 months during the first two years after ovarian cancer treatment, then extending intervals based on individual risk factors.
Timing considerations include avoiding testing during menstruation when possible, as CA-125 levels can be significantly elevated during menses. For post-chemotherapy patients, wait at least three weeks after treatment for accurate interpretation.
How do I interpret the results?
CA-125 Level: 0–35 U/mL
- What it means: Normal range
- Typical action: Continue routine screening if high-risk
CA-125 Level: 35–100 U/mL
- What it means: Mildly elevated
- Typical action: Consider benign causes; clinical correlation needed
CA-125 Level: 100–500 U/mL
- What it means: Moderately elevated
- Typical action: Requires further evaluation with imaging studies
CA-125 Level: >500 U/mL
- What it means: Significantly elevated
- Typical action: Strongly suggests malignancy; urgent evaluation needed
Approximately 97% of healthy women with elevated CA-125 levels do not have ovarian cancer, highlighting the importance of clinical correlation.
Normal CA-125 levels range from 0-35 U/mL, though some laboratories use slightly different reference ranges up to 36 U/mL (Cleveland Clinic 2025). Results must always be interpreted within clinical context, considering symptoms, family history, and imaging findings.
Elevated levels don't automatically indicate cancer. Many benign conditions can cause CA-125 elevation, including endometriosis, ovarian cysts, menstruation, pregnancy, and liver disease. Serial testing often provides more valuable information than single measurements, particularly for establishing individual trends and baseline values.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
CA-125 testing requires no fasting and minimal preparation, making it highly convenient for routine monitoring (Apollo Hospitals). However, several important considerations can affect result accuracy.
Discontinue biotin supplements at least 72 hours before testing, as biotin interference can cause falsely decreased CA-125 levels (Healthcare University of Iowa 2017). This includes biotin-containing multivitamins and hair/nail supplements.
Avoid testing during menstruation when possible, as CA-125 levels can be significantly elevated during menses, potentially leading to misinterpretation. Schedule testing at least one week after menstrual period completion for most accurate results.
For post-treatment patients, wait at least 3 weeks after chemotherapy and 2 months after abdominal surgery before testing, as these interventions can temporarily affect CA-125 levels independent of disease status.
How often should I get tested?
- High-risk screening (BRCA positive): Every 6–12 months
- Post-treatment surveillance (Years 1–2): Every 3–4 months
- Post-treatment surveillance (Years 3–5): Every 6 months
- Long-term survivors (5+ years): Annually or as directed
- Endometriosis monitoring: Every 6–12 months
- Baseline establishment: 2–3 tests over 12 months
Testing frequency depends primarily on individual risk factors and clinical circumstances. Cancer survivors require the most intensive monitoring, with quarterly testing during the first two years when recurrence risk peaks, then gradually extending intervals based on continued remission.
High-risk individuals with BRCA mutations or strong family histories benefit from biannual testing combined with clinical examinations and imaging studies. This approach enables early detection while avoiding excessive testing anxiety.
Endometriosis patients may benefit from periodic CA-125 monitoring to track disease progression and treatment response, though testing intervals should align with symptom patterns and treatment protocols.
Why early detection matters
Ovarian cancer remains the deadliest gynecologic malignancy, with approximately 12,730 deaths projected in the United States for 2025 (American Cancer Society 2025). The disease's reputation as a "silent killer" stems from its tendency to remain asymptomatic until advanced stages.
Five-year survival rates demonstrate the critical importance of early detection: localized ovarian cancer carries a 93% five-year survival rate, while advanced-stage disease drops to just 31%. Unfortunately, only 18% of cases are diagnosed at early, localized stages.
CA-125 monitoring enables proactive surveillance for high-risk individuals and cancer survivors, potentially detecting recurrence months before symptoms develop. This early warning system allows for prompt intervention when treatments are most effective and survival outcomes optimal.
Global projections indicate ovarian cancer cases will increase 55% by 2050, emphasizing the growing importance of effective screening strategies for at-risk populations (World Ovarian Cancer Coalition 2024).
Related tests you may consider
Human Epididymis Protein 4 (HE4) serves as a complementary ovarian cancer biomarker with superior specificity (93% vs 78% for CA-125) and enhanced early-stage detection when combined with CA-125 testing (PMC 2019). This combination improves diagnostic accuracy for distinguishing malignant from benign pelvic masses.
Cancer Screening Panel, Women – A comprehensive blood test panel that measures key tumor markers and organ function indicators to help detect potential signs of cancer commonly affecting women, supporting early detection and proactive health management.
Cancer Antigen 19-9 (CA 19-9) offers additional tumor marker insights, particularly useful for detecting mucinous ovarian cancer subtypes and pancreatic malignancies. Multi-marker panels combining CA-125, HE4, and CA 19-9 enhance overall diagnostic accuracy for various gynecologic and abdominal cancers.
