What Is CA-125?
CA-125 stands for cancer antigen 125, a protein that can be measured through a simple blood test.
It is often called an ovarian cancer marker because its level may increase in women with certain types of ovarian cancer.
However, CA-125 is also present in people without cancer. An elevated CA-125 result does not automatically mean ovarian cancer.
Why Might Your Doctor Recommend a CA-125 Test?
CA-125 is particularly useful in women who have already been diagnosed with ovarian cancer. Repeated measurements can help doctors monitor treatment and look for signs that the disease may have returned.
It may also be requested when an ultrasound reveals a mass or cyst near an ovary, especially when further assessment is needed.
In these situations, CA-125 provides additional information alongside imaging, symptoms, age, and medical history.
The blood test alone cannot determine whether an ovarian mass is benign or malignant.
What Can Cause Elevated CA-125 Levels?
Several noncancerous conditions can increase CA-125, including:
- Endometriosis, where tissue similar to the lining of the uterus grows outside the uterus.
- Menstruation and pregnancy.
- Uterine fibroids.
- Pelvic inflammation or infection.
- Certain liver diseases.
CA-125 can also rise in some cancers outside the ovaries.
This is why an abnormal result must always be interpreted in its clinical context.
What Is a Normal CA-125 Level?
Many laboratories use approximately 35 units per millilitre as a reference threshold, although ranges may vary.
A result above this level does not establish a cancer diagnosis.
Equally, a normal CA-125 result cannot exclude ovarian cancer, particularly in its early stages.
Doctors therefore consider the result together with other findings rather than relying on a single number.
Can CA-125 Detect Ovarian Cancer Early?
CA-125 can contribute to the investigation of suspected ovarian cancer, but it is not recommended as a routine screening test for women without symptoms who have an average risk of the disease.
Some early ovarian cancers do not produce elevated CA-125 levels. At the same time, benign conditions can cause false alarms.
For women with a strong family history or inherited cancer risk, specialist assessment is important to determine an appropriate prevention and monitoring strategy.
When Should You Seek Medical Advice?
Persistent abdominal bloating, pelvic discomfort, feeling full unusually quickly, or frequent urination should not be ignored, particularly when these symptoms are new or occur repeatedly.
Your doctor may recommend a pelvic ultrasound and, when appropriate, a CA-125 test.
The goal is to investigate concerning symptoms promptly, rather than relying on a blood test alone.
