direct antiglobulin test

Direct anti-human globulin test is an important basis for the diagnosis of autoimmune hemolytic anemia (AIHA), check the presence or absence of incomplete antibodies on the red blood cells, also known as Coombs' test. The direct test is to check for the presence of incomplete antibodies on the red blood cells examined, and the indirect test is to check for free incomplete antibodies in the serum. The direct Coombs' test is more diagnostic than the indirect test for AIHA. AIHA can be divided into three types by using specific monovalent antiserum: IgG/C3 positive, accounting for 67%; IgG alone, accounting for 20%; C3 alone, accounting for 13%. Basic Information Specialist classification: growth and development examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Normal value: no Above normal: negative: Negative is generally normal. Positive: Common in autoimmune anemia. Tips: pay attention to rest and diet, blood on an empty stomach. Normal value The direct anti-human globulin test was negative. Clinical significance Abnormal result Positive test 1. Autoimmune anemia, hemolytic anemia caused by (IgG) type, the direct reaction of this test is often strongly positive. 2. Drug-induced immune hemolytic anemia, combined with indirect reactions to disease. 3. The cold agglutinin syndrome is directly positive. 4. Neonatal allogeneic hemolytic disease, hemolytic disease caused by Rh blood group incompatibility, direct strong positive, lasting for several weeks, transfusion within a few days after transfusion can be negative, due to "ABO" blood group incompatibility caused by hemolytic disease, the results often Negative or weakly positive. 5. The transfusion reaction caused by the incompatibility of red blood cell type, ABO or Rh blood type is not transfusion, the donor's red blood cells are sensitized by the recipient's blood group antibody, and the direct reaction is positive before the donor is completely destroyed by the sensitized red blood cells. 6. Others in infectious mononucleosis, SLE, malignant lymphoma, chronic lymphocytic leukemia, cancer, lead poisoning, nodular periarteritis, Evan's syndrome, etc., the patient's direct response can also be positive, array In patients with chilly hemoglobinuria, the direct response to anti-complement serum after an acute attack is often positive. The people who need to be examined have weak, weak, sleepy, pale skin, mucous membranes, palpitations, dizziness, headache, tinnitus, vertigo, inattention, and lethargy. Positive results may be diseases: autoimmune hemolytic anemia, Rh blood group incompatibility hemolytic disease, pediatric autoimmune hemolytic anemia, warm antibody type autoimmune hemolytic anemia considerations Taboo before the test: pay attention to rest and diet, blood on an empty stomach. Requirements for examination: Direct Coombs' test with heparin or EDTA anticoagulation. Inspection process Vascular blood collection was used for testing. Before venous blood collection, carefully check that the needle is securely installed and that there is air and moisture in the syringe. The needle used should be sharp, smooth, ventilated, and the syringe should not leak. Firstly, the skin was disinfected from the inside to the outside and clockwise from the selected venipuncture with a 30g/L iodine swab. After the iodine was volatilized, the iodized trace was wiped out in the same way with a 75% ethanol swab. Fix the lower end of the venipuncture site with the thumb of the left hand, hold the syringe syringe with the thumb and middle finger of the right hand, and fix the needle lower seat with the index finger, so that the bevel of the needle and the scale of the syringe are upward, and the needle is inclined along the vein to make the needle and the skin obliquely penetrate the skin at an angle of 30°. Then, through the vein wall, enter the venous cavity forward at an angle of 5°. After seeing the blood return, the needle will be probed into the spot to avoid the needle slipping out when the blood is collected; but it is not possible to use a deep puncture to avoid hematoma, and immediately remove the cuff. Needle plug can only be pumped out, can not be pushed in, so as to avoid injecting air into the vein to form a gas plug, causing serious consequences. Remove the syringe needle and slowly inject the blood into the anticoagulation tube along the tube wall to prevent hemolysis and foam. Not suitable for the crowd 1. Patients who have taken contraceptives, thyroid hormones, steroid hormones, etc., may affect the results of the examination and prohibit patients who have recently taken the drug history. 2, special diseases: patients with hematopoietic function to reduce disease, such as leukemia, various anemia, myelodysplastic syndrome, etc., unless the examination is essential, try to draw less blood. Adverse reactions and risks 1, subcutaneous hemorrhage: due to pressing time less than 5 minutes or blood draw technology is not enough, etc. can cause subcutaneous bleeding. 2, discomfort: the puncture site may appear pain, swelling, tenderness, subcutaneous ecchymosis visible to the naked eye. 3, dizzy or fainting: in the blood draw, due to emotional overstress, fear, reflex caused by vagus nerve excitement, blood pressure decreased, etc. caused by insufficient blood supply to the brain caused by fainting or dizziness. 4. Risk of infection: If you use an unclean needle, you may be at risk of infection.

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