Serum Immunoglobulin A (IgA)

IgA accounts for 10% to 20% of the total serum immunoglobulin and can be divided into serotype and secretory type. Secretory IgA is the major immunoglobulin in exocrine fluids such as colostrum, saliva, tears, intestinal secretions, and bronchial secretions. Therefore, it plays an important role in the first line of anti-infective defense, especially in the respiratory tract and intestines, which can be called "local immunity." Basic Information Specialist classification: cardiovascular examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Tips: Do not eat too greasy, high-protein foods the day before the blood draw, avoid heavy drinking. The alcohol content in the blood directly affects the test results. After 8 pm on the day before the medical examination, you should start fasting for 12 hours to avoid affecting the test results. Normal value Immunoturbidimetric radioimmunoassay (RID method) Umbilical cord 0 ~ 50mg / L (0 ~ 5mg / dl). Newborns 0 ~ 22mg / L (0 ~ 2.2mg / dl). 0.5-6 months 30 to 820 mg/L (3 to 82 mg/dl). 6 months - 2 years old 140 ~ 1080mg / L (14 ~ 108mg / dl). 2-6 years old 230 ~ 1900mg / L (23 ~ 190mg / dl). 6-12 years old 290 ~ 2700mg / L (29 ~ 270mg / dl). 12-16 years old 810 ~ 2320mg / L (81 ~ 232mg / dl). Adults 760 ~ 3900mg / L (76 ~ 390mg / dl). (Note the specific reference value depends on each laboratory.) Clinical significance (1) The increase is more common in IgA multiple myeloma, systemic lupus erythematosus (SLE) sarcoidosis, rheumatoid arthritis, Behcet syndrome, portal cirrhosis, certain infectious diseases, eczema, thrombocytopenia, Wiskott-Aldrich syndrome (multiple infections of eczema thrombocytopenia), chronic bronchitis remission period, etc. Secretory IgA between 500 and 2500 mg / L is a serious condition, and the course of disease is <500 mg / L. Umbilical cord blood IgA increases rubella, herpes simplex, toxoplasmosis cytomegalovirus, Coxsackie virus, Gram-negative bacilli intrauterine infection. (2) reduction is more common in Hereditary telangiectasia (80%), non-IgA multiple myeloma, heavy chain disease, light chain disease, malabsorption syndrome, primary disease-free globulinemia, secondary proteinemia, Secondary non-gammaglobulinemia, secondary immunodeficiency disease (radiation exposure, use of immunosuppressants), repeated respiratory infections, transfusion reactions, autoimmune diseases, nephrotic syndrome, chronic lymphocytic leukemia, Hodgkin Disease, hereditary thymic hypoplasia, gamma globulin abnormality type III gamma globulin abnormality type I (IgG, IgA reduction, IgM increase), gamma globulin abnormality type II (no IgA, IgM, IgG normal) )Wait. High results may be diseases: small intestinal allergic purpura, linear IgA bullous skin disease, pediatric selective immunoglobulin G subtype deficiency disease considerations First, the precautions before blood draw 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. Second, should pay attention after blood draw 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 A. Selection of antiserum concentration: The square matrix titration is carried out with the reference product. The principle of optimal dilution is to maintain the excess of the antibody, the linear range is wide, and the turbidity is higher after the reaction with the corresponding Ig. B. Standard curve: Dilute the Ig reference to different concentrations: IgG 5.0, 9.0, 13.0, 17.0, 21.0 g/L; IgA 1.0, 2.0, 3.0, 4.0, 5.0 g/L; IgM 0.5 1.2, 1.9, 2.6, 3.3g/L. Three dilution tubes were set for each dilution, 25 μl per tube. Add the optimal dilution antisera to 2.5 ml per tube. After a 37 ° C water bath for 1 h (IgG) or 2 h (IgA, IgM), the absorbance was measured at 495 nm using a turbidimeter or a colorimeter. The Ig concentration is plotted on the abscissa and the absorbance is plotted on the ordinate. C. Specimen test: The test procedure is the same as the preparation standard curve. When IgG was measured, the serum to be tested was diluted 1:40; the IgA and IgM were diluted 1:5. A standard curve was prepared simultaneously for each batch of tests, and a standard control (sample plus dilution) and antiserum control were set. Not suitable for the crowd There are no special taboos. Adverse reactions and risks No related complications and hazards.