What tests should be done for influenza in children? 4 methods of testing for influenza in children

(1) Virus isolation: Use acute nasopharyngeal wash, pharyngeal gargle or pharyngeal swab for examination. It is best to immediately inoculate chicken embryo amniotic cavity or allantoic sac, or inoculate sensitive human embryo kidney and other cell cultures to isolate influenza virus. If necessary, inoculate experimental animals to isolate the virus. The specimen should be collected within 3 to 5 days. If it is too late, the positive rate will be reduced.

(2) Hemagglutination and hemagglutination inhibition test: The ability of influenza virus to agglutinate guinea pig red blood cells (or chicken and human (or chicken and human) O red blood cells) is to mix early nasopharyngeal wash fluid (washed with saline) with guinea pig red blood cells. A positive agglutination test only indicates the presence of the virus, and the reaction sensitivity is poor. If a specific anti-influenza virus serum is added in advance for a hemagglutination inhibition test, a positive result indicates that the specimen contains influenza virus, and this method can be used for further classification and identification.

(3) Fluorescent staining to examine nasal mucosal cells: Rotate a nasopharyngeal swab several times in the nasal cavity to stain the swab with mucosal exfoliated cells and apply it to a glass slide. After drying, stain with fluorescent antibodies (anti-influenza virus specific serum). Under a fluorescent microscope, many cells with apple green fluorescence appear positive. Pay attention to identifying nonspecific fluorescent spots. Positive results have positive significance, while negative results cannot be completely excluded. This method is very fast (completed within 2 hours).

(4) Serum antibody testing: ① hemagglutination inhibition test, ② neutralization test, and ③ complement fixation test can be used. When the serum antibody titer during the recovery period exceeds 4 times the initial titer, the positive rate can generally reach 60%~80%.