The principle of microcolumn gel cross matching test: in the micro column gel medium, red blood cell antigen binding with corresponding antibody, using gel steric hindrance by low speed centrifugation, red blood cell aggregation in suspension and gel layer, without antibodies bind to red blood cells sink at the bottom of the gel (tube bottom tip).
The advantages of microcolumn gel cross matching test: micro column gel experiment (aka microcolumn gel card) results were clear and stable results can be saved, high sensitivity, strong specificity, standardized operation, high automation, detection of IgG antibody and less amount of sample and reduce the error rate the advantages of. Common problems of cross matching blood test with microcolumn gel clamp:
1,the main side is not agglutination, sub side agglutination
 1.1 microcolumn gel cross matching test if the primary side and secondary side agglutination, agglutination, the reasons are: the red blood cell has been coated with antibody (antibody, direct antiglobulin test is positive for DAT). The most common causes are patients with immune system diseases, tumors, and Department of orthopedics patients. Blood donors have antibodies against red blood cells. The ABO blood group incompatibility between the patient and the donor.
 1.2 treatment
 1.2.1Red cell direct antihuman globulin test in patients with 1.2.1: Patients with 05% red cell suspension 50ul were added to the main or lateral side of the blood clamp, and immediately centrifuged 5min (900rpm2min; 1500rpm3min). The program has been set up Take out the naked eye to determine the result. If a positive result, the patient's red blood cells, red blood cells of patients have been sensitized, this bag of blood can be issued, but the report clearly written: the main side of clots, side agglutination of red blood cells in patients with positive direct antiglobulin test, please slow infusion.
 1.2.2If the patient's red cell direct anti globulin test is negative, the presence of incomplete antibodies in the donor plasma is determined. Incomplete antibody screening test for blood donors plasma: 08% red cell suspension I, II and III of the 50ul (1 drops) with the corresponding gel tube, plus blood donors plasma 50ul, 37 DEG C and incubated for 15min centrifugal 5min (900rpm2min; 1500rpm3min. The program has been set up Take out the naked eye to judge the result. If the result is positive, it indicates that there is incomplete antibody in the plasma of the donor. The blood of the bag cannot be sent out and must be changed into a bag of blood and re combined with blood.
 1.2.3If the cause is not found, please re - collect the blood sample and re - sample the blood with the new specimen.
2,Main side agglutination, second side does not agglutinate.
2.1,Micro column gel cross matching blood test if the main side of the agglutination, the second side is not agglutinate, the reasons are: first, patients or blood donors ABO typing is incorrect, or two of the ABO blood group does not match. The specificity of some subtypes is very strong. There were antibodies in the serum of the patients and reacted with the corresponding antigens on the red blood cells of the donors. The red blood cells of the donors have already been coated with antibodies. The patient's serum is abnormal and the patient has just been transfused with a macromolecular drug, such as dextran.
2.2 treatment re identification of blood type, such as blood type errors, then re use the same type of blood and blood. If it is of subtype, the bag blood can not be sent out, and a bag of blood must be changed to re fit the blood. If the patient has just been transfused with a macromolecular drug such as dextran, immediately stop the infusion of the macromolecular drug, and then take the blood sample again after 2h, and then re union the blood.
3,Primary and secondary sides are all agglutination.
 3.1 Micro column gel cross matching test, if the primary and secondary sides are aggregated, mainly due to the ABO blood type errors.
 3.2 To handle the detection of blood recipients and donors of ABO blood group (positive and negative stereotypes), must use ABO and RHD blood typing reagent card (monoclonal antibody) (microcolumn gel) as a blood test, if the positive and negative stereotypes inconsistent to deal with according to the corresponding method, until the results can make a reasonable explanation so far.
Note: anti human globulin gel blood must be marked with the name of the patient and the blood donor bag number (after 4), one card can be three bags of blood. Preparation of micro column gel card: first, observe the appearance of micro column gel card before blood collection, such as dry glue, impurities, bubbles can not be used, and then use a special centrifuge centrifuge 3~4min. The concentration of RBC suspension should not be too strong or too weak, so 0.5%~0.8% should be appropriate. In winter, normal saline can be incubated with red blood cell suspension at 37 DEG C. In case of difficulty, red blood cells can be washed by warm saline to identify blood type and blood. Serum and red blood cell suspension should be added to the reaction chamber. The suspicious agglutination, then centrifugal 5min, and then observe the results. The serum or plasma samples must be fully to fibrin, otherwise specimens of fibrin in micro column gel precipitation, hinder the negative erythrocyte sedimentation, false positive reaction or mixed agglutination. If the supernatant of plasma sample contains floc or granule, the supernatant can be centrifuged to make fibrin sink. When red cell suspension is applied, the suction head is applied to the bottom of the tube to avoid inhalation of fibrin. Blood samples of blood donors must be centrifuged, and the blood vessels and blood vessels at the juncture of blood vessels contain large amounts of fibrin and should be cut off at the junction. The drug can cause some diseases, such as blood cross matching incompatibility, which should be distinguished. Abnormal serum protein and bacteria can affect the results of 9. The microcolumn gel card should be placed in the 18~25 C storage, should pay attention to prevent heavy pressure and high temperature.
In short, microcolumn gel cross matching test found do not match (on one side or both sides of agglutination agglutination), should first consider the recipients and donors were ABO typing is wrong, you must re identification of blood type, including RH blood group, must do irregular antibody screening test. Second, we should pay attention to the presence of specific antibodies and specific unknown antibodies. If the serum of the patient is agglutinated at room temperature, 37 DEG C or anti globulin, and all other red blood cells cause difficulty in cross matching test, the patient should be referred to the supervisor or director in time. Ask the superior blood center to guide and solve the problem when necessary.
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