What Is CA 125?
What Is CA 125 Measurement Used to Diagnose?
CA 125 is commonly used:
- To help diagnose ovarian cancer in women at risk
- To detect recurrent ovarian cancer in women who have been previously treated
- To help predict treatment outcome in women with ovarian cancer and closely related cancers, such as fallopian tube and primary peritoneal cancers
- To monitor or assess treatment effectiveness
- To screen for ovarian, primary peritoneal, and fallopian tube cancers in high-risk women or in women with abnormal findings on examination or ultrasound
- Used as a marker to help determine the risk of a malignancy preoperatively
What Are Limits of the CA 125 Test?
Limits of the CA 125 test include:
- CA 125 is only elevated in about half of women who have early-stage ovarian cancer and 85% of women with advanced ovarian cancer
- This means a woman may have ovarian cancer and her levels of CA 125 may not be elevated
- Levels of CA 125 do not correlate with how much disease a person has
- Many noncancerous conditions can also increase CA 125 levels, such as
- The National Cancer Institute and the United States Preventive Services Task Force do not recommend use of CA 125 measurements to screen women who have a low risk for developing ovarian cancer
What Level of CA 125 Indicates Cancer?
The normal range for CA 125 is 0 to 35 units/ml.
If you have not been diagnosed with ovarian cancer, high levels will require further testing to make a diagnosis.
If you have been treated for ovarian cancer, and CA 125 levels are high, it may mean the cancer has returned.
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