Thrombomodulin antigen

Thrombomodulim (TM) is a member of a new class of cell adhesion molecules with lectin-like activity. TM is a receptor for thrombin, which functions like cadherin. It is known to be expressed in many normal tissues of humans and can also be expressed in many tumor tissues, but its physiological and pathological significance is still poorly understood.

Basic Information

Specialist classification: cardiovascular examination classification: biochemical examination

Applicable gender: whether men and women apply fasting: fasting

Tips: Before the examination, the diet is light and alcohol is prohibited. Check for an empty stomach in the morning. Normal value

RIA method

20 to 35 μg / L (plasma).

Clinical significance

Elevated in diabetes, systemic lupus erythematosus (SLE), disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura, acute myocardial infarction, cerebral infarction, pulmonary embolism, occlusive vasculitis.

High results may be diseases: thromboangiitis obliterans, acute myocardial infarction, thrombotic thrombocytopenic purpura, disseminated intravascular coagulation, cerebral infarction, diabetes precautions

The expression of TM in gastric cancer tissues was significantly higher in patients over 60 years old.

Inspection process

Immediately after blood collection, the test method 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

Inappropriate people: Generally there are no people who are not suitable.

Adverse reactions and risks

1, local subcutaneous hemorrhage: after the blood collection should be pressed for a sufficient time, especially those with bleeding tendency, so as not to cause subcutaneous oozing and bruising due to no blood coagulation.

2, infection: attention to aseptic operation during venous blood collection, so as not to cause local infection.