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Cancer-embryonic antigen in the blood.
Last reviewed: 04.07.2025
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Reference values (norm) of the concentration of carcinoembryonic antigen (CEA) in blood serum are 0-5 ng/ml; in alcoholics - 7-10 ng/ml; in smokers - 5-10 ng/ml. Half-life is 14 days.
Carcinoembryonic antigen is a glycoprotein formed during embryonic development in the gastrointestinal tract. The content of carcinoembryonic antigen is affected by smoking and, to a lesser extent, alcohol consumption. A slight increase in the content of carcinoembryonic antigen is observed in 20-50% of patients with benign diseases of the intestine, pancreas, liver and lungs. The main use of carcinoembryonic antigen is to monitor the development of the disease and the effectiveness of therapy in patients with colorectal carcinoma. The sensitivity of the test is:
- colorectal cancer - 50% at a concentration of more than 7 ng/ml;
- liver cancer - 33% at a concentration of more than 7 ng/ml;
- breast cancer - 28% at a concentration of more than 4.2 ng/ml;
- gastric cancer - 27% at a concentration of more than 7 ng/ml;
- lung cancer - 22% at a concentration of more than 7.4 ng/ml.
The content of carcinoembryonic antigen in the blood serum of patients with colon cancer correlates with the stage of the disease and serves as an indicator of the effectiveness of surgical intervention, chemotherapy and radiation therapy. Carcinoembryonic antigen can be used as an early indicator of relapses and metastases. In untreated malignant tumors, the level of carcinoembryonic antigen constantly increases, and in the initial stage its growth is pronounced.
Increased levels of carcinoembryonic antigen in the blood may accompany pancreatic cancer. The sensitivity and specificity of carcinoembryonic antigen for diagnosing pancreatic cancer are 63.3 and 81.7%, respectively. The levels of carcinoembryonic antigen also increase in some patients with pancreatitis, which reduces the value of using this marker.
An increased concentration of carcinoembryonic antigen in the blood serum is detected in 30-50% of patients with breast cancer and in 33-36% of patients with lung cancer.
Diseases and conditions that increase the level of carcinoembryonic antigen
Cancer |
Sensitivity,% |
Non-cancerous diseases |
Sensitivity,% |
Colon and rectum |
70-80 |
Emphysema of the lungs |
20-50 |
Pancreas |
60-90 |
Active ulcerative colitis |
10-25 |
Lungs |
65-75 |
Alcoholic cirrhosis |
25-70 |
Stomach |
30-60 |
Cholecystitis |
6-20 |
Breast |
50-65 |
Rectal polyps |
4-20 |
| Ovary | 40 |
Benign breast diseases | 4-15 |
Other carcinomas |
20-50 |
Determination of the content of carcinoembryonic antigen in blood serum is used:
- for monitoring the course and treatment of rectal cancer (an increase in concentration to 20 ng/ml is a diagnostic sign of malignant tumors of various localizations).
- for monitoring tumors of the gastrointestinal tract, lungs, and mammary glands;
- for early diagnosis of relapses and metastases of cancer;
- for monitoring in risk groups (cirrhosis, hepatitis, pancreatitis).
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