4.1 Widal test Flashcards
Serological test used for diagnosis of enteric fever or typhoid fever
Widal test
Who developed Widal test?
Greenbaum and Widal in 1896
Typhoid or enteric fever is caused by?
Salmonella enterica (typhi, paratyphi)
Salmonella possess O antigen contains?
Cell Wall
Salmonella possess H antigen contains?
Flagella
Widal test is an precipitation test
T or F
F
Agglutination test
Typhoid fever antibodies are detected by mixing patient’s serum with killed bacterial suspension of Salmonella carrying specific O, H, AH, and BH antigens and observe for clumping
T or F
T
Widal test can be done in two ways which are ?
Tube and slide
In quantitative tube test what is the incubation temp and duration?
37 C for 16-20hrs
Antibody titre greater than 1 : 80 is considered significant and usually suggests positive test for Salmonella infection
T or F
T
Widal test is time consuming to find antibody titre and often times when diagnosis is reached it is too late to start an antibiotic regimen
T or F
T
Widal test may be falsely Negative in patients who have had previous vaccination or infection with S.Typhi
T or F
F
False Positive
Widal test cannot distinguish between a current infection and a previous infection or vaccination against typhoid.
T or F
T
Widal test shows cross-reactivity with other Salmonella species.
T or F
T
