CA 125 Test

The CA 125 test is a blood test used to measure the level of a protein called cancer antigen 125 (CA 125) in the blood.

What is CA 125?

CA 125 is a type of glycoprotein that is normally produced by cells in the body, particularly in the epithelial tissues of the ovary, uterus, and other organs. In healthy individuals, the level of CA 125 in the blood is usually low.

Purpose of the Test

The primary purpose of the CA 125 test is to monitor women with ovarian cancer, particularly those with epithelial ovarian cancer, which accounts for about 90% of all ovarian cancers. The test can help:

• Detect early signs of ovarian cancer recurrence in women who have already been treated for the disease
• Monitor the effectiveness of treatment for ovarian cancer
• Help diagnose ovarian cancer, although it is not a definitive diagnostic tool

How the Test is Performed

A healthcare provider will draw a blood sample from a vein in the arm using a needle and syringe. The blood sample is then sent to a laboratory for analysis.

Interpretation of Results

The results of the CA 125 test are usually reported as a numerical value, measured in units per milliliter (U/mL). A level of:

• 0-35 U/mL is generally considered normal
• 36-50 U/mL may indicate a benign condition or early ovarian cancer
• 51-100 U/mL may indicate ovarian cancer, but can also be seen in other conditions such as endometriosis or pelvic inflammatory disease
• Above 100 U/mL is often associated with advanced ovarian cancer

Limitations of the Test

The CA 125 test has several limitations, including:

• It can produce false-positive results in women with benign conditions such as endometriosis, uterine fibroids, or pelvic inflammatory disease
• It can miss some cases of ovarian cancer, particularly in the early stages
• It is not specific to ovarian cancer and can be elevated in other types of cancer, such as breast, lung, or pancreatic cancer

Risk Factors for Elevated CA 125 Levels

Certain factors can increase the risk of an elevated CA 125 level, including:

• Pregnancy
• Menstruation
• Endometriosis
• Uterine fibroids
• Pelvic inflammatory disease
• Liver or kidney disease

Conclusion

The CA 125 test is a useful tool for monitoring women with ovarian cancer, but it has limitations and should be used in conjunction with other diagnostic tests and clinical evaluations to confirm a diagnosis.

Frequently Asked Questions (FAQs)

What is a CA 125 test?
Blood test measuring CA 125 protein levels.

Why is the CA 125 test done?
To monitor ovarian cancer and its treatment.

What does a high CA 125 level indicate?
Possible ovarian cancer or other conditions.

Can a high CA 125 level be caused by non-cancerous conditions?
Yes, such as endometriosis or pregnancy.

How is the CA 125 test performed?
Blood sample drawn from a vein.

Is the CA 125 test a definitive diagnostic tool?
No, further testing is needed for diagnosis.

What are normal CA 125 levels?
Typically less than 35 units per milliliter.

Can the CA 125 test detect early ovarian cancer?
Not always, as levels may not be elevated in early stages.

How often should the CA 125 test be repeated?
As recommended by a healthcare provider.

Are there any risks associated with the CA 125 test?
Minimal risk of bleeding or bruising at the needle site.