sugar chain antigen 72-4

The carbohydrate antigen CA72-4 (CA72-4) is a high molecular weight mucin molecule with a molecular weight greater than 1000 kD. It is recognized by monoclonal antibodies B72-3 and CC49 and is prepared by cancer cell membrane immunization of breast cancer liver metastases. CA72-4 is also a tumor marker for gastrointestinal and ovarian cancer. Basic Information Specialist classification: Oncology examination classification: immune examination Applicable gender: whether men and women apply fasting: fasting Tips: Try to eat less and eat as much as possible, and arrange your diet reasonably. Normal value <6kU/L. Clinical significance 1. The serum CA72-4 level of lung cancer patients is often significantly increased. CA72-4 is also different in different pathological types. The undifferentiated and poorly differentiated cancer is the highest, and the moderately and highly differentiated cancer is the second. Dynamic measurement of serum CA72-4 level has important clinical significance for the monitoring, efficacy evaluation and recurrence diagnosis of lung cancer. 2, serum CA72-4 levels can also be found in gastric cancer, colorectal cancer, ovarian cancer and breast cancer and other malignant tumors, dynamic determination of serum CA72-4 level is conducive to the above-mentioned tumor disease monitoring, efficacy evaluation and recurrence diagnosis. 3. The combined detection of serum CA72-4 and CEA has complementary effects on the diagnosis of the above malignant tumors. High results may be diseases: lung cancer, stomach cancer, ovarian cancer, colon cancer, rectal cancer, pancreatic cancer CA72-4 is superior to glycoprotein antigens 19-9 and CEA in the diagnosis of gastric cancer. Before inspection: 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. Fasting for 12 hours before taking blood, taking fresh blood for inspection. When checking: When you draw blood, you should relax your mind, avoid the contraction of blood vessels caused by fear, and increase the difficulty of blood collection. After inspection: 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. Inspection process Immediately after the blood samples are collected, they are sent for examination and tumor immunoassay. The detection procedure is divided into three steps, namely antigen-antibody reaction, B and F separation, and radioactivity determination. 1. Antigen and antibody reaction: The specimen (non-labeled antigen), labeled antigen and antiserum are sequentially dosed into a small test tube, and allowed to stand at room temperature (15-30 ° C) for 24 hours to fully compete for binding. 2, B, F separation: a variety of separation techniques, commonly used precipitation method. 1 second antibody precipitation method: also known as diabody method, after the test antigen specifically reacts with the first antibody, the corresponding second antibody is added, so that the formed antigen-first antibody-second antibody complex is co-precipitated. The labeled antigen B is separated from the free antigen F by centrifugation. This method is a specific precipitation, complete separation, low non-specific binding. However, the amount of the second antibody is large and the cost is high. In addition, the serum concentration and the presence or absence of anticoagulants can affect the results to some extent. 2 Polyethylene glycol (PEG) precipitation method: the protein is in an isoelectric point state, and the hydration layer is destroyed to cause protein precipitation. The advantage of this method is that PEG is convenient to prepare, inexpensive, and rapid to separate. The disadvantage is that there are many non-specific precipitates and the separation is incomplete. 3Second antibody-polyethylene glycol precipitation method: This method not only has the advantage of rapid precipitation of PEG method, but also maintains the effect of specific precipitation of second antibody, reduces the amount of second antibody, and reduces the concentration of PEG, so that non-specific precipitation Reduced material. 4 Activated carbon adsorption method: the free part of small molecules is adsorbed by the surface activity of activated carbon. For example, a layer of dextran is coated on the surface of the activated carbon to make a mesh having a certain pore diameter on the surface, thereby allowing small molecules of free antigen or hapten to escape and being adsorbed, while the macromolecular complex is excluded. After the antigen and the antibody are reacted, the dextran-activated carbon is added and allowed to stand for 5 to 10 minutes, so that the free antigen is adsorbed on the activated carbon particles, and the particles are precipitated by centrifugation, and the supernatant contains the labeled antigen. 3. Determination of radioactivity: After separation of B and F, the radioactivity can be determined. There are two types of measuring instruments: a liquid scintillation counter (measuring beta rays) and a crystal scintillation counter (measuring gamma rays). The unit of counting is the number of electrical pulses output by the detector in units of cpm (number of pulses/min). A standard curve is required for each measurement, and the different concentrations of the standard antigen are plotted on the abscissa, and the corresponding radioactivity measured is plotted on the ordinate. The radioactivity may be optionally B or F, and the calculated values ​​B/B+F, B/F or B/B0 may also be used. Specimens should be determined in duplicate, the average value is taken, and the corresponding antigen concentration is detected on the standard curve. Not suitable for the crowd Those without examination indications should not be tested. Adverse reactions and risks 1. Infection: Pay attention to aseptic operation during venipuncture, pay attention to local cleaning after puncture, prevent water pollution and avoid infection. 2, bleeding: puncture needle damage to local blood vessels or tissue caused by local bleeding, should try to avoid puncture too deep.

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