Vidal reaction

Reaction Vidal - agglutination reaction used for the diagnosis of typhoid fever and some Tivo-partypany diseases. To various dilutions of the serum of the patient's blood type washing away crops pathogen (typhoid fever, paratyphoid) or diagnosticums - standard solutions of antigens (see). After conditioning in the thermostat comes agglutination in the form of grains, cereals, precipitating. Reaction Vidal convenient, simple, but has a low specificity: in severe forms of the disease or when using antibiotics results may be negative because of the loss of ability to form antibodies. On the contrary, the positive reaction Vidal sometimes found he underwent abdominal typhoid or paratyphoid (anamnestic response), and after vaccination (vaccination reaction). Reaction Vidal should be placed multiple times (from 6-9 days of the disease), as the diagnostic value has increased titer agglutinins in the period of the disease. Cm. also Serological studies.