Antiplatelet Antibodies (APA)

Antiplatelet is an antibody that binds to platelets and is a target for the diagnosis of autoimmune thrombocytopenia. The antibody-bound platelets are either easily captured by the mononuclear-macrophage system or are dissolved by binding to complement, resulting in shortened platelet life and reduced number. Clinically determined by ELISA. ELISA is a highly sensitive test technique that combines the specific reaction of antigens and antibodies with the efficient catalysis of enzymes on substrates based on immunological reactions. Since the reaction of the antigen and the antibody is carried out in the well of a solid phase carrier, a polystyrene microtiter plate, after each reagent is added, the excess free reactant can be removed by washing to ensure the specificity of the test result. And stability. Basic Information Specialist classification: examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Normal value: no Above normal: negative: normal. Positive: Positive for platelet autoimmune diseases caused by various causes. Tips: After 8 pm on the day before the medical examination, you should start fasting for 12 hours, so as not to affect the test results. Normal value (1) ABC-ELISA method 1.9 to 5.5 ng / 106 · platelets. (2) Double antibody sandwich ELISA method PAIgG0.0-78.8 ng/107·platelets. PAIgM 0.0 ~ 7.0 ng / 107 · platelets. PAIgA 0.0 ~ 2.0 ng / 107 · platelets. (3) Enzyme-linked immunosorbent competition method 0.0 to 3.0 fg/platelet. (4) Qualitative negative. Clinical significance Abnormal results are elevated (positive): 1, drug-induced platelet antibodies, more common in the use of quinidine, thiazide diuretics, digoxin, heparin. 2, platelet autoantibodies, more common in primary thrombocytopenic purpura, systemic lupus erythematosus, chronic lymphocytic leukemia, rheumatoid arthritis, sepsis. 3, platelet alloantibodies, more common in maternal and child platelet incompatibility, platelet incompatibility, neonatal alloimmune thrombocytopenia, transfusion after purpura. Need to check patients with primary thrombocytopenic purpura, systemic lupus erythematosus, chronic lymphocytic leukemia, rheumatoid arthritis, sepsis and other patients. Positive results may be diseases: Pregnancy with idiopathic thrombocytopenic purpura Forbidden before examination: Please inform the doctor about the recent medication and special physiological changes before the test. 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. Requirements for 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 There are many methods for measuring platelet antibodies, and the most commonly used method in the country is ELISA. The principle of PAIgG measurement is to add a sample to be tested (or a different concentration of standard solution) to a reaction plate coated with an antibody against human IgG, and the IgG in the sample is specific to the anti-human IgG antibody coated on the plate. Sexual binding, the enzyme labeling plate is added to the reaction plate after washing, and finally the substrate is colored, the color depth is proportional to the IgG content on the surface of the platelet membrane, and the IgG content of the sample to be tested can be obtained according to the standard curve. . The principle of determination of PAIgA, IgM and PAC3 is the same. Not suitable for the crowd Inappropriate people: generally no special population. Adverse reactions and risks There are no related complications and hazards.