What tests doctors use to find ovarian cancer

There is no single screening test that reliably catches ovarian cancer early in people without symptoms. Instead, doctors use a combination of physical exam, blood tests, and imaging to investigate when symptoms appear or when risk factors are present. The most common approach starts with a pelvic ultrasound and a blood test called CA-125, which measures a protein that ovarian cancer cells often produce in high amounts.

If those initial tests suggest cancer might be present, a CT scan or MRI provides detailed images of the pelvis and abdomen. The only way to confirm ovarian cancer is a biopsy—a tissue sample taken during surgery or through a needle—because imaging alone cannot distinguish cancer from benign cysts or other conditions.

Key Takeaways

  • A pelvic ultrasound and CA-125 blood test are the standard first steps when symptoms or risk factors suggest ovarian cancer.
  • CT or MRI scans show whether a mass has spread, but imaging cannot confirm cancer without a tissue sample.
  • A biopsy—tissue examined under a microscope—is the only definitive way to diagnose ovarian cancer.
  • Genetic testing for BRCA1 and BRCA2 mutations can identify people at higher risk, even before symptoms appear.
  • Most ovarian cancers are found at an advanced stage because early tumors rarely cause noticeable symptoms.

Pelvic ultrasound and what it shows

A pelvic ultrasound is usually the first imaging test ordered. A technician moves a small probe over your lower abdomen and inside the vagina to create detailed pictures of the ovaries, fallopian tubes, and surrounding tissue. The test takes 20 to 30 minutes and causes no pain, though the internal probe can feel uncomfortable.

The ultrasound can show the size, shape, and texture of an ovarian mass and whether it appears solid or filled with fluid. Cysts that look simple and smooth are usually benign, while masses with thick walls, solid areas, or irregular shapes raise concern for cancer. However, ultrasound cannot definitively prove cancer is present—that requires a biopsy.

CA-125 blood test and its limitations

CA-125 is a protein released by ovarian cancer cells into the bloodstream. A simple blood draw measures the level, and results come back within days. A CA-125 level above 35 units per milliliter is considered elevated and may prompt further testing.

The problem is that CA-125 is not specific to cancer. Benign ovarian cysts, endometriosis, menstruation, pregnancy, and even some infections can raise CA-125. About 20 percent of early-stage ovarian cancers do not produce elevated CA-125 at all. For this reason, doctors use CA-125 alongside ultrasound and clinical symptoms rather than relying on it alone.

CT and MRI scans for staging and spread

If ultrasound and CA-125 suggest cancer is likely, a CT (computed tomography) or MRI (magnetic resonance imaging) scan follows. These tests create cross-sectional images of the pelvis and abdomen and can show whether a tumor has spread to lymph nodes, the liver, or other organs—information that determines the stage of cancer and guides treatment decisions.

CT scans are faster and more widely available; MRI provides better detail of soft tissue and is sometimes preferred when the diagnosis is uncertain. Both require you to lie still for 15 to 45 minutes. CT uses radiation, while MRI uses magnetic fields and is safer in pregnancy, though it takes longer and is not suitable if you have certain metal implants.

Biopsy: the only way to confirm cancer

A biopsy is a tissue sample examined under a microscope by a pathologist. It is the only test that can definitively diagnose ovarian cancer and determine what type it is. There are two main ways to obtain a sample: during surgery or through a needle.

A needle biopsy uses imaging (ultrasound or CT) to guide a thin needle into the mass while you are awake with local anesthesia. The procedure takes 15 to 30 minutes and carries a small risk of bleeding or infection. A surgical biopsy happens during a procedure called a laparoscopy, where a surgeon inserts a thin camera through a small cut in the abdomen to see the ovaries and take a sample, or during open surgery if a larger sample is needed. Surgical biopsy is more invasive but allows the surgeon to examine the entire pelvis and remove tissue if cancer is confirmed.

Genetic testing for BRCA mutations

Genetic testing looks for mutations in the BRCA1 and BRCA2 genes, which significantly increase the risk of ovarian and breast cancer. A simple blood test or saliva sample is sent to a lab, and results take one to two weeks. Testing is recommended for anyone diagnosed with ovarian cancer and for people with a family history of ovarian or breast cancer, especially if relatives were diagnosed before age 50.

A positive BRCA result does not mean you have cancer—it means your risk is much higher than average. If you carry a mutation, your doctor may recommend more frequent screening, preventive surgery to remove the ovaries, or preventive medications. Genetic counseling before and after testing helps you understand what the results mean for your health and your relatives' health.

Why early detection is difficult

Ovarian cancer is often called a "silent killer" because early-stage tumors rarely cause symptoms. Many women do not notice anything wrong until the cancer has spread beyond the ovaries to the peritoneum (the lining of the abdomen) or other organs. By that point, the cancer is stage 3 or 4, and treatment is more complex.

Symptoms that do appear—bloating, pelvic pain, difficulty eating, or urinary urgency—are vague and easily mistaken for digestive or urinary problems. This is why there is no routine screening test for ovarian cancer in people without symptoms or known risk factors. Testing is reserved for people with symptoms, a family history of ovarian cancer, or a known BRCA mutation.

Frequently Asked Questions

Can ovarian cancer be detected with a regular pap smear?

No. A pap smear screens for cervical cancer, not ovarian cancer. It samples cells from the cervix, not the ovaries. If you have symptoms or risk factors for ovarian cancer, you need a pelvic ultrasound and blood tests, not a pap smear.

What does a normal CA-125 result mean?

A normal CA-125 (below 35 units per milliliter) makes ovarian cancer less likely but does not rule it out completely. About one in five early-stage ovarian cancers have a normal CA-125. If you have symptoms or imaging findings that concern your doctor, further testing may still be needed.

Is a biopsy always necessary if imaging looks suspicious?

Yes, in most cases. Imaging cannot tell the difference between cancer and benign conditions with certainty. A biopsy is the only way to know whether a mass is cancer, what type it is, and how aggressive it is—all information your doctor needs to plan treatment.

What happens if I have a BRCA mutation but no cancer?

A BRCA mutation means your lifetime risk of ovarian cancer is 35 to 70 percent, depending on which gene is mutated. Your doctor may recommend more frequent screening with ultrasound and CA-125, preventive removal of the ovaries and fallopian tubes, or preventive medications. Genetic counseling can help you decide what is right for your situation.

How long does it take to get a diagnosis after testing starts?

It varies. An ultrasound and blood test take days to a week. If those suggest cancer, a CT or MRI adds another week. A needle biopsy can be done within days, but results take a few days to a week. A surgical biopsy may take longer if surgery needs to be scheduled. In total, from first test to confirmed diagnosis is often two to four weeks.