CA-125 (Ovarian Cancer Marker)
Measures CA-125 protein levels to help monitor ovarian cancer treatment or screen individuals at high risk.
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What this test measures
CA-125 is a blood test that measures the amount of the protein CA-125, also called cancer antigen 125, in the body. CA-125 is an antigenic determinant on a high-molecular-weight glycoprotein and contains more than 11,000 amino acids in its proteinaceous core. CA-125 is expressed by more than 80% of nonmucinous epithelial ovarian carcinomas and is found in most carcinomas of Müllerian origin, including fallopian tube and primary serous peritoneal carcinoma.
CA-125 is a type of biomarker or a substance in blood that may be a sign of a condition or disease. A high level of CA-125 can be a sign of ovarian cancer. However, elevated CA-125 levels may also occur in various benign conditions. 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. The test is most commonly used to monitor treatment response in those already diagnosed with ovarian cancer and to screen individuals at very high risk for the disease. No doctor visit required - individuals can order this test directly and receive results confidentially.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals with a family history of ovarian cancer, particularly those with BRCA gene mutations or multiple affected relatives
- Those being monitored during or after treatment for ovarian, fallopian tube, or primary peritoneal cancer
- Postmenopausal individuals with unexplained pelvic symptoms or suspicious pelvic masses
- Patients with a personal history of ovarian cancer who need regular surveillance for recurrence
- Those with genetic predisposition syndromes associated with increased ovarian cancer risk
What to expect
Preparation
No fasting is required. Stop biotin supplements at least 72 hours before collection. Avoid testing during menstruation when possible, as CA-125 levels can be elevated during menses. Schedule testing at least one week after menstrual period completion for most accurate results.
Sample Type
A simple blood draw from a vein in the arm
Collection
A healthcare professional will clean the collection site, insert a small needle into a vein, and draw the blood sample. The process typically takes just a few minutes.
Turnaround
Results are typically available within 1-2 business days after the sample reaches the laboratory
Understanding your results
The reference range of CA 125 is 0-35 units/mL (0-35 kU/L). The normal CA 125 level is less than 35 units per milliliter (U/mL) of blood. Results must be interpreted in conjunction with clinical symptoms, imaging studies, and other diagnostic tests. CA-125 testing shouldn't be used for people who have no symptoms or risk factors for ovarian cancer, and it doesn't detect cancer on its own. The test is most meaningful when used for monitoring disease progression or treatment response in those already diagnosed.
| Population | Reference Range | Notes |
|---|---|---|
| Adults (All) | 0-35 U/mL | Normal range for healthy individuals |
Reference ranges shown are general guidelines. Your lab report will include the specific reference range used by the laboratory that processed your sample, which is the authoritative range for interpreting your results.
What does a “Low” result mean?
CA-125 levels within the normal range (0-35 U/mL) typically indicate the absence of the conditions that commonly elevate this marker. However, normal levels do not rule out recurrence in those with a history of ovarian cancer. Some individuals with early-stage ovarian cancer may have normal CA-125 levels. It is possible to get a normal ovarian cancer marker range in results, and a normal report does not rule out the possibility of cancer. For this reason, healthcare providers rely on multiple diagnostic approaches including imaging studies and physical examination alongside CA-125 testing.
What does a “High” result mean?
Anything over 35 U/mL is considered elevated. 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. However, elevated CA-125 levels may indicate various conditions beyond ovarian cancer. 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, as well as benign conditions including cirrhosis, hepatitis, endometriosis, first trimester pregnancy, ovarian cysts, and pelvic inflammatory disease. In individuals already diagnosed with ovarian cancer, rising levels may suggest disease progression or treatment resistance.
Privacy & confidentiality
All test orders are authorized and results reviewed by an independent, board-certified physician who is not the patient's personal doctor. Your CA-125 test results are completely confidential and handled with the utmost discretion. Results are __not reported to your doctor__ unless you specifically choose to share them. This test is __not part of your medical records__ maintained by your healthcare provider or health system. The test __will not appear on insurance statements__ or explanation of benefits (EOB) forms, ensuring complete privacy. Your results are not shared with employers, insurance companies, or any third parties. This confidential testing allows individuals to monitor their health status privately, particularly important for sensitive cancer marker screenings where individuals may want to assess their risk or monitor their condition discreetly before involving their healthcare provider.
Frequently asked questions
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CPT Code: 86304
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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