ca-125 blood test

What is CA-125 Blood Test? Ovarian Cancer Treatment and Symptoms

With the advancement of medical science the terms ovarian cancer and CA-125 blood test have become almost synonymous. The term “ovarian cancer” includes different types of cancers, all of which arise from the cells of the ovary. In most cases, cancerous tumors arise from the epithelium or lining cells of the ovary. These include epithelial ovarian, fallopian tube and primary peritoneal cancer. There are less common forms of ovarian cancer as well – that arise from the ovary itself, such as germ cell tumors and sex-stromal tumors. Women who are suspected of having ovarian cancer and those who have been diagnosed with ovarian cancer are suggested to do CA125 Blood Test which measures their CA 125 levels.

Symptoms of Ovarian Cancer

Before getting on with the CA-125 Test, let us know the Ovarian Cancer Symptoms:

  • Abdominal bloating, pressure and pain
  • Abdominal fullness after eating
  • Difficulty in eating
  • Increase in urination
  • Increased urge to urinate
  • Fatigue
  • Indigestion
  • Heart burn
  • Constipation
  • Back pain
  • Menstrual irregularities
  • Painful intercourse

What is a CA-125 Blood Test?

The CA-125 blood test is for ovarian cancer diagnosis and monitoring. In order to know what the CA-125 test is all about, let us first know what is CA-125. Well, CA125 is a glycoprotein found in the blood and it is commonly referred to as a biomarker or tumor marker because it provides information about the state of ovarian cancer. In order to measure the level of CA125 a blood sample is taken from the veins. But it must be taken in to account that an elevated CA125 level does not always indicate ovarian cancer and absence of CA125 does not always mean that the disease is absent. CA125 test can sometimes misinterpret a biological state. But, it is still considered an important tool for diagnosis of ovarian cancer because serial changes in CA 125 levels can be a representative of the disease statues and helpful in assessment of the treatment.

Why is the CA-125 Blood Test Done?

The CA125 test plays an important role in ovarian cancer treatment and it is done in a variety of situation during the course of diagnosis, treatment and follow-up of ovarian cancer because it helps in detecting, monitoring and screening the disease.

Outcome Prediction:

CA125 has been assessed for its ability to predict the treatment outcome for women suffering from ovarian cancer and other closely related cancers such as fallopian tube and primary peritoneal cancer. Studies show that if a woman is treated for ovarian cancer for the very first time and her CA125 level returns to normal then she will have a better chance of survival. But the result of the study is based on the trends for large groups of women and it not a suitable predictor for individual women.


CA 125 test is the most reliable ovarian cancer test to detect recurrent ovarian cancer in women, who have been treated previously. Rising level of CA125 over a series of tests strongly indicate that there is a recurrence of the disease. But, some women develop a recurrence even without a rising CA125 level and in other women there is a slight rise in the CA 125 value but never full recurrence of the disease.


CA 125 test is done throughout the course of chemotherapy in order to monitor the effectiveness of the treatment. The CA 125 test is a reliable tool which is used in conjunction with physical exams and thorough history of the patient in order to understand whether the treatment is working or not. But the monitoring is most accurate when the patient has an elevated initial CA-125 value. Most doctors depend on how the test result change over time rather than just one test result.


CA-125 test is also used to screen for ovarian cancer, primary peritoneal cancer and fallopian tube cancer in high-risk women or women with abnormal ultrasound results. Researchers suggest using several tests including CA-125 test in sequence or together in order to diagnose ovarian cancer in high-risk women.

How is the CA-125 Blood Test Performed?

The CA-125 test involves a simple blood test and no special preparation is required for it. During the test a small sample of blood is taken from a vein in the arm. The healthcare provider cleans and disinfects the area with an antiseptic and once he finds a vein he will insert the needle into it and collect the blood sample in a small tube which will be sent to a laboratory for analysis. After the needle is removed the puncture site will be covered in order to stop any bleeding.

CA125 Test Results

CA-125 is one of the most widely used ovarian cancer blood tests and the standard CA-125 level is 35 U/mL.
Normal results – A CA-125 level below 35U/mL is considered normal, but the normal value ranges may vary slightly in different labs.

Abnormal Results:

Woman who has ovarian cancer:

A rise in CA-125 level above 35U/mL means the disease is progressing or is has recurred. Decrease in CA-125 level means that the disease is responding to the current treatment.

Woman who has not been diagnosed with ovarian cancer:

A rise in CA-125 level may mean a number of things. While it may indicate than she has ovarian cancer, it can also mean she has other type of cancer or any other disease like endometriosis. A woman with abnormal CA-125 test requires further tests to confirm the disease.

Factors that Affect CA-125 Test Results

There are a number of health conditions and disorders that can cause elevated CA-125 levels:

  • Pregnancy
  • Menstruation
  • Fallopian tube cancer
  • Noncancerous growth in the uterus – uterine fibroids
  • Endometriosis
  • Pelvic inflammatory disease
  • Cancer of the pancreas

The CA-125 test is a simple procedure and abnormal result does not mean you have ovarian cancer. The test is done by the doctor in order to rule out certain conditions and to decide what other tests, procedures, follow up care and additional treatment is required.

Medically Reviewed By
Dr. Kaushal M. Bhavsar (MBBS, MD)Assistant Professor in Pulmonary Medicine, GMERS Medical College, Ahmedabad