Test Quick Guide

Cancer antigen 125 (CA-125) is a protein that may be found at higher levels in people with certain types of cancer and other health conditions. The CA-125 test checks the levels of this protein in the blood.

The CA-125 test is a type of tumor marker test. This test is used in monitoring a patient’s response to ovarian cancer treatment, and detecting recurrence of ovarian cancer after treatment.

About our CA-125 Test

Purpose of the test

The purpose of a CA-125 test is to measure the amount of CA-125 in the blood. Although this protein may be elevated in several health conditions and multiple types of cancer, testing is typically reserved for patients with suspected or confirmed ovarian cancer. A doctor may order a this test for several reasons:

  • Diagnosing a pelvic mass:

CA-125 testing may be used to help determine if a pelvic mass seen on an imaging test could be related to ovarian cancer. CA-125 may be elevated in many epithelial ovarian cancers, but not all ovarian cancers cause high CA-125 levels, especially in earlier stages.

  • Screening in high-risk patients:

CA-125 may be used, often with other tests, in some patients at very high risk of developing ovarian cancer due to hereditary cancer syndromes, such as those with inherited BRCA1 and BRCA2 gene mutations. It’s not recommended as a routine screening for people at average risk, but is recommended for women with a family history of hereditary ovarian cancer in conjunction with physical examination and ultrasound testing.

  • Evaluating treatment response:

Testing levels of CA-125 helps doctors monitor how well a patient’s ovarian cancer is responding to treatment.

  • Estimating prognosis:

Although not all expert groups agree, some recommend measuring levels of CA-125 to help estimate a patient’s prognosis or chance of recovery from ovarian cancer.

  • Monitoring for cancer recurrence:

Monitoring the level of CA-125 helps doctors check for signs of a return of cancer after a patient has completed treatment for ovarian cancer. However, routine monitoring has not been shown to improve outcomes and may lead to unnecessary treatment in some people

It’s important to note that a normal CA-125 level does not rule out ovarian cancer, because some ovarian cancers don’t elevate this protein and levels may remain normal early in the disease. Depending on the clinical situation, providers may also use Human Epididymis Protein 4 (HE4) alongside CA-125 when evaluating or monitoring epithelial ovarian cancer.

What does our CA-125 test measure?

CA-125 testing measures the amount of the CA-125 protein found in the blood. CA-125 is measured in units per milliliter, or U/mL.

Both cancerous and noncancerous conditions may affect blood CA-125 levels. Many healthy cells produce low levels of CA-125, including cells of the ovaries, pancreas, breast, and lining of the chest and abdomen. Cancer and other health conditions that cause irritation or inflammation in these organs can increase CA-125 levels.

Conditions that may cause an elevated CA-125 level in the blood include:

  • Ovarian cancer
  • Cancers of the pancreas, breast, fallopian tube, colorectal, gastrointestinal tumors, and lung
  • Endometriosis
  • Uterine fibroids
  • Early Pregnancy
  • Menstruation
  • Liver disease
  • Cirrhosis
  • Hepatitis
  • Pericarditis

A CA-125 result alone can’t diagnose ovarian cancer – diagnosis requires follow-up evaluation, and confirmation usually depends on biopsy and pathology.

Finding a CA-125 Test

How to get tested

The CA-125 test is ordered by a doctor or other health care provider. The blood draw for this test may take place in a laboratory, clinic, doctor’s office, or hospital.

Can I take the test at home?

CA-125 testing is usually performed on a blood sample collected in a clinic, lab, or other health care setting. Direct-to-consumer or mobile collection options may be available, but this varies by provider and location.

How much does the test cost?

The cost of a CA-125 test may depend on where you have the test performed and your health insurance coverage. The total cost of the test can include the office visit, the technician’s fees for obtaining the blood sample, and the laboratory’s fees for performing the test.

If your doctor has prescribed a CA-125 test for you, your insurance provider usually covers these fees and costs. Patients may be responsible for some out-of-pocket costs, such as  deductibles and copayments. Your doctor, insurance provider, and laboratory staff can give you more information about the cost of CA-125 testing.

 

Taking a CA-125 Test

The CA-125 test is performed on a sample of blood. To obtain the sample, a health professional uses a small needle to draw blood from a vein.

Before the test

You generally don’t need to prepare in any specific way before CA-125 testing. To make sure the test is as accurate as possible, you should talk to your doctor if you are taking any prescription medications or over-the-counter drugs.

During the test

A CA-125 test is a simple blood test. A health care provider collects a small blood sample from a vein in your arm, which is then sent to a laboratory for analysis.

You may feel a slight pain or stinging when the needle is inserted or removed, but this is usually mild and does not last long. The entire procedure usually takes no more than five minutes.

After the test

Risks are minimal after a CA-125 test. After your blood is drawn, the technician will apply a small bandage to stop any bleeding. You may need to keep this in place for an hour or more.

Generally, you can return to normal activities after having this test. Rarely, people who have their blood drawn may feel lightheaded, continue to bleed, or develop an infection where the blood was taken. Contact your doctor if you notice any of these symptoms.

FAQs About CA-125 Test

Can CA-125 levels go up and down over time?

Yes. CA-125 levels can fluctuate due to both cancerous and noncancerous conditions. Because of this, your provider may look at trends over time rather than relying on a single test result.

If my CA-125 level is high, does that mean I have ovarian cancer?

Not necessarily. Elevated CA-125 levels can be caused by many noncancerous conditions, including menstruation, endometriosis, pelvic inflammatory disease, and even pregnancy. A high result means more evaluation may be needed, but it’s not a diagnosis of cancer.

If my CA-125 level is normal, does that mean I don’t have cancer?

No. A normal CA-125 result does not rule out ovarian cancer. Some people with ovarian cancer – especially in earlier stages – may have normal CA-125 levels. That’s why results are always interpreted alongside symptoms and other tests.

Will I need more than one CA-125 test?

Possibly. In some situations, your provider may recommend repeat testing to monitor changes in CA-125 levels over time. This can help provide a clearer picture than a single result.

Does an elevated CA-125 mean the ovarian cancer has come back?

Not always. While rising CA-125 levels can be a sign of recurrence in some people, they can also increase for other reasons. Your provider will usually consider changes over time and may order additional tests before determining whether cancer has returned.