Carcinoembryonic Antigen (CEA)

Carcinoembryonic antigen was first found in colon cancer and fetal intestinal tissue, hence the name. Elevated serum CEA, in addition to gastrointestinal cancer, is also seen in other systems. Continuous monitoring of carcinoembryonic antigen levels can be used for therapeutic observation and prognosis of tumor therapy. The serum carcinoembryonic antigen level is generally decreased when the condition is improved, and the disease is elevated when the disease progresses. Basic Information Specialist classification: Oncology examination classification: immune examination Applicable gender: whether men and women apply fasting: fasting Tips: A large number of smokers, serum carcinoembryonic antigen can also be elevated. Normal value <5.0 μg/L. Clinical significance CEA is mainly used for clinical monitoring of colorectal cancer, gastric cancer, pancreatic cancer, hepatocellular carcinoma, lung cancer, breast cancer and thyroid medullary cancer. It is also found in choriocarcinoma, bone cancer, prostate cancer and ovarian cancer, but has no early diagnostic value. . The serum carcinoembryonic antigen level is generally decreased when the condition is improved, and the disease is elevated when the disease progresses. In addition, a mild increase in CEA is also seen in certain benign digestive tract diseases such as intestinal obstruction, biliary obstruction, pancreatitis, cirrhosis, colon polyps, ulcerative colitis, and smokers and the elderly. Serum CEA is temporarily elevated in 25% of these patients with benign gastrointestinal diseases. High results may be diseases: cancer, pediatric pineal region tumor, pediatric mediastinal cyst and tumor, vaginal leiomyosarcoma, pediatric saddle germ cell tumor, vaginal adenocarcinoma, vaginal intraepithelial neoplasia, diffuse mesothelioma, vagina Metastatic tumor, carcinoma in situ First, the precautions before blood draw 1, do not eat too greasy, high-protein food the day before the blood, to avoid heavy drinking. The alcohol content in the blood directly affects the test results. 2. After 8 pm on the day before the medical examination, you should start fasting for 12 hours to avoid affecting the test results. 3, should relax when taking blood, to avoid the contraction of blood vessels caused by fear, increase the difficulty of blood collection. Second, should pay attention after blood draw 1. After blood is drawn, local compression is required at the pinhole for 3-5 minutes to stop bleeding. Note: Do not rub, so as not to cause subcutaneous hematoma. 2, the pressing time should be sufficient. There is a difference in clotting time for each person, and some people need a little longer to clotting. Therefore, when the surface of the skin appears to be bleeding, the compression is stopped immediately, and the blood may be infiltrated into the skin due to incomplete hemostasis. Therefore, the compression time is longer to completely stop bleeding. If there is a tendency to bleed, the compression time should be extended. 3, after the blood draw symptoms of fainting such as: dizziness, vertigo, fatigue, etc. should immediately lie down, drink a small amount of syrup, and then undergo a physical examination after the symptoms are relieved. 4. If there is localized congestion, use a warm towel after 24 hours to promote absorption. 3. Please inform the doctor about the recent medication and special physiological changes before the test. Fourth, the separation of serum for examination, the specimen should not be hemolysis. Fifth, pay attention to the rise of preoperative carcinoembryonic antigen, should be reviewed regularly. The first review is performed 6 weeks after surgery; every 3 months in 3 years, once every 3 months in 3 to 5 years; once every 5 years, if it is elevated, it indicates recurrence or metastasis, and serum carcinoembryonic antigen is It has increased 3 to 12 months before symptoms and signs appear. Inspection process 1. Blood collection test: 2ml of venous blood is taken on an empty stomach to avoid hemolysis and pollution. If the test cannot be sent in time, the serum should be separated and stored at -20 °C. Tumor immunoassay was performed after the test. 2. Radioimmunoassay: The carcinoembryonic antigen labeled with a known amount of radionuclide is mixed with the non-labeled carcinoembryonic antigen in the sample to be tested, so that the two compete against each other for the same specific antibody. In the case where the amount of the labeled antigen and the antibody is constant, when the amount of the labeled antigen and the detected antigen is larger than the binding point of the antibody, the higher the concentration of the detected antigen, the less the labeled antigen binds to the antibody, so that the more free labeled antigen. Thus, the radioactivity in the free antigen or the bound antigen is measured, and a graph of the relationship between the antigen and the amount of the antigen can be plotted to calculate the measured antigen content. Not suitable for the crowd Those without examination indications should not be tested. Adverse reactions and risks 1. Infection: Pay attention to aseptic operation when collecting blood, avoid contamination of water and other parts at the blood collection site to avoid local infection. 2, bleeding: after the blood is given a full compression time, especially coagulopathy, bleeding tendency, to avoid local subcutaneous oozing, bruising and swelling.