CEA Carcinoembryonic Antigen Test (CEA Test)

CEA test

It is a blood test that detects CEA (carcinoembryonic antigen) levels in blood. CEA is a protein formed by gastrointestinal tissue at the time of foetal development. Its production declines as pregnancy advances and stops before birth of the baby. Hence blood CEA levels are very low or negligible in healthy adults. Its levels is about 0-2.5 ng/ml.

However its blood levels increases in certain cancerous and non-cancerous conditions. Hence it is a type of tumour marker (those chemicals which are produced by cancer cells into bloodstream) whose levels help in assessment of response of treatment. The different types of cancers where CEA levels increase are:

• Colon and rectal cancer
• Prostate cancer
• Cancer of ovary
• Lung cancer
• Thyroid cancer
• Liver cancer
• Pancreatic cancer

High CEA levels is also seen in non-cancerous conditions like liver cirrhosis, emphysema, certain breast diseases, cholecystitis, pancreatitis, peptic ulcer, ulcerative colitis and rectal polyps. Its high levels are also seen in smokers.

Why is CEA blood test prescribed?

This test is prescribed in the following situations:

• To monitor effectiveness of treatment of CEA producing cancers. The treatment may include surgery, chemotherapy and/or radiotherapy. Serial monitoring of CEA should begin prior to therapy for verifying post therapy reduction in CEA blood levels and to establish a baseline for evaluating possible recurrence. CEA blood levels will return to normal in about 1-4 months after treatment.
• To monitor aggravation of previously diagnosed cancer.
• To monitor if there is recurrence of cancer after treatment. Any increase in CEA levels over time in a patient with history of cancer suggest tumour recurrence.
• To detect size of tumour and amount of spread of the tumour-if the CEA levels are low before start of treatment it shows that tumour size is small and it has not spread extensively. If the levels are high it signifies that tumour is of large size and/or it has spread to other parts of the body. CEA blood levels should not be used to screen asymptomatic individuals for cancers. Use CEA levels in conjunction with information from clinical evaluation of the patient and other diagnostic procedures.

Procedure and prerequisites

The sample for CEA test is taken from blood (serum) by inserting a small needle into vein of your arm. A small amount of blood is then collected in test tube or vial. You may feel some pain due to needle prick. No particular preparation is needed for this test.

Reference range

Normal range-0-2.5 ng/ml (non- smokers)

Smokers may have elevated levels of CEA usually less than 5 ng/ml.

Extensive disease->10 ng/ml

Metastatic cancer->20 ng/ml