A CA-125 blood work determines the amount of cancer antigen 125 present in the bloodstream. Cancer antigen 125 (CA-125) is a protein molecule found in ovarian cancer cells. This type of protein is produced by the cells and can be found in the blood. This test is used to check ovarian cancer during and after treatment. It is also used to monitor for early signs of ovarian cancer in women who are at risk for the disease. However, CA-15 blood test is not precise enough to detect ovarian cancer in all women, as several other health problems can lead to abnormal CA-125 levels.

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CA-125 Test - Cancer Antigen 125

Why Is A CA-125 Blood Test Performed?

CA-125 blood work is mostly done to analyse the progression of ovarian cancer. Baseline CA-125 levels are measured before a patient undergoes treatment for ovarian cancer. A drop in CA-125 levels during and after treatment indicated that treatment has been successful. While elevated CA-125 levels following treatment may suggest a relapse of the disease.

Post-treatment for ovarian cancer, the CA-125 blood test is repeated for several years to confirm the disease was cured successfully. It’s usually recommended every 2 to 4 months for the first two years following the completion of cancer treatment. After this interval, the test is repeated every 6 months for the next three years and then once per year. Women with a high risk of ovarian cancer like those with mutations in the BRCA1 and BRCA2 genes, which may increase the risk of breast and ovarian cancers, should consider periodic CA 125 testing. Furthermore, doctors may also recommend the CA-125 blood test to women with a strong family history of ovarian cancer. Also, there are several disorders and conditions that can cause elevated CA-15 levels, such as


Normal menstruation

Liver cirrhosis

Endometrial and fallopian tube cancers

Uterine fibroids


Pelvic inflammatory disease

Cancer of the pancreas

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How Is A CA-125 Blood Test Performed?

A sample of blood is usually collected from a vein in the arm. The technician will clean and disinfect the area with an antiseptic, then an elastic band is tied around the upper arm, so that the veins swell with blood. Once a vein is found, a needle is gently inserted into the vein and blood is drawn into a small tube attached to the needle. The blood sample collected will be sent to a laboratory for analysis.

 Risks Of A CA-125 Blood Test?

This test is a low-risk procedure. However, at times there may be some risks common to all blood tests that include:

Difficulty to draw a blood sample, which may result in several needle pricks

Excessive bleeding at the puncture site

Fainting due to blood loss

Infection at the puncture site

What Does Test Results Mean?

CA -125 blood test results vary depending on the laboratory the test is analysed.CA-125 levels are high if the values are above 35 units per ml.

High levels don’t necessarily confirm the presence of ovarian or any other type of cancer. Certain cancer medications and surgeries may at times alter the results. You should talk with your physician regarding test results and find out if any further evaluation is needed. The CA-125 blood test is also used to evaluate the effectiveness of ovarian cancer treatments. Where high levels of CA-125 mostly denote that patient is not responding to the cancer treatment. In such a case, a person may need alternative treatments to combat the disease. Whereas a low level of CA-125 means the patient is responding well to cancer treatment.

Additionally, some women with ovarian cancer may have normal baseline levels of CA1-25 that indicate the tumours aren’t producing the CA1-125 protein. In such cases, a CA-125 test wouldn’t help the healthcare provider to evaluate the progression of ovarian cancer.