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CA-125 blood test

A CA 125 test blood test measures the amount of protein CA 125 (cancer antigen 125). This test can help monitor certain cancers during treatment or afterwards. Sometimes, the test may check for early ovarian cancer signs in people with a high risk of this disease.

The CA 125 test is not accurate enough to be a general ovarian cancer screening because several conditions can increase this protein level. These conditions are not always cancerous, such as uterine fibroids and menstruation. Certain cancers can also increase the CA 125 levels, including endometrial, ovarian, fallopian tube and peritoneal cancers.

What is the test for?

Your doctor may order the CA 125 test for different reasons, such as:

  • Cancer treatment monitoring

    If you have endometrial, fallopian tube, ovarian, or peritoneal cancer, your doctor may recommend a CA 125 test regularly to monitor the treatment and your condition.

    However, the monitoring hasn’t been shown to improve the results for people with ovarian cancer and often leads to additional, unnecessary rounds of chemotherapy or other treatments.

  • Screening for ovarian cancer for people with high-risk

    Your doctor may recommend a CA 125 test to screen for ovarian cancer if you have an inherited gene that elevates your risk of having this disease or a family history of ovarian cancer. Some doctors recommend CA 125 testing and transvaginal ultrasound every 6 – 12 months for people at a very high risk.

    However, some people with ovarian cancer do not have an increased level of CA 125, and no evidence has shown that this screening reduces the possibility of dying of ovarian cancer. Increased levels of CA 125 may cause your doctor to recommend unnecessary and harmful tests.

  • Check for recurring cancer.

    Increasing levels of CA 125 may indicate a recurrence of ovarian cancer after treatment. Regular CA 125 monitoring hasn’t been shown to improve the outcome of people with ovarian cancer and may result in additional and unnecessary chemotherapy or other treatment.

    If your doctor suspects you have ovarian or another type of cancer, you may need additional tests. Other tests that aid in evaluating these cancers include pelvic or transvaginal ultrasound, MRI, CT scan and serum human epididymis protein 4 (HE4). A biopsy (a procedure that requires removing a small cell sample for testing) may be necessary to confirm the diagnosis.

Why is a CA 125 blood test necessary?

If you have an ovarian cancer diagnosis, you may need several CA 125 blood tests.

  • During treatment to determine whether your cancer is going away – if the CA-125 levels are reducing, the treatment may be effective.
  • After the treatment to check if the cancer is recurring
  • If you have a high risk for ovarian cancer, your doctor may order CA-12 5 tests. If the CA 125 level is high, you will need more tests for an accurate diagnosis. You are at risk of getting ovarian cancer if you:

Have an inherited gene or conditions that increase your risk of ovarian cancer. These include changes in your BRCA 1 or BRCA 2 genes, previous breast, colorectal or uterine cancer, and Lynch syndrome (also known as hereditary non-polyposis colorectal cancer). This genetic disorder increases the risk of having several types of cancer.

  • If you have a lump in your pelvis that may indicate ovarian cancer, a biopsy is necessary to help diagnose ovarian cancer.

If you have concerns about getting ovarian cancer, consult your doctor.

What does the CA 125 blood test involve?

The CA 15 blood test involves taking a small blood sample for testing. You may feel a small sting or prick when the needle enters your arm. The blood sample collection takes only a few minutes and has no dietary restrictions.

What is the normal range for a CA 125 result?

The healthcare provider will interpret your result. The normal ranges may vary from laboratory to laboratory. Generally, CA 125 levels higher than 35 units per millilitre are normal. However, high levels don’t always indicate cancer or recurring cancer. You will discuss your results with your doctor to determine their meaning and if you need additional testing.

  • Normal range of CA 125

    The measurement for CA 125 levels is in units per millimetre (U/mL). The normal CA 125 levels are between 0 – 35U/ml. Levels above 35U/mL may mean cancerous cells are present or other conditions. Some patients with high CA 125 levels do not have cancer.

    A high result may need additional testing for women without a history of ovarian cancer, but for women who have had ovarian cancer, this result may mean a cancer recurrence.

How can I get my result?

Your doctor will inform you how long the test will take and when your results will be available, including how to find out the result of the test. In most cases, you can access your results online and ask your doctor for more information.

Ensure you contact your doctor if you haven’t gotten your result within two weeks or you have gotten your result and are unsure what it means.

If your CA 125 result exceeds 35 U/Ml, your doctor will likely arrange a follow-up or further testing.

If you are concerned about your risk of ovarian cancer, visit Blood London for CA 125 testing or call us on 020 7183 0244 to book an appointment with our doctor. You can also contact us for more information on CA 125 tests.

How Blood London Works

Order your test

Order your test

Select the test that you would like to undergo

Provide your sample

Provide your sample

Go to the Harley Street clinic for your blood draw and pay for your test in person

View your results

View your results

As soon as the results are ready, the will be sent to you by your chosen method

World class partner lab (TDL)

World class partner lab (TDL)

Advice from expert UK doctors

Advice from expert UK doctors

Repeat your tests and track your improvements!

Repeat your tests and track your improvements!

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