Evaluation of the Widal tube agglutination test for the diagnosis of typhoid fever among children admitted to a rural hdospital in Tanzania and a comparison with previous studies.
BACKGROUND
The diagnosis of typhoid fever is confirmed by culture of Salmonella enterica serotype Typhi (S. typhi). However, a more rapid, simpler, and cheaper diagnostic method would be very useful especially in developing countries. The Widal test is widely used in Africa but little information exists about its reliability.


METHODS
We assessed the performance of the Widal tube agglutination test among febrile hospitalized Tanzanian children. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of various anti-TH and -TO titers using culture-confirmed typhoid fever cases as the "true positives" and all other febrile children with blood culture negative for S. typhi as the "true negatives."


RESULTS
We found that 16 (1%) of 1,680 children had culture-proven typhoid fever. A single anti-TH titer of 1:80 and higher was the optimal indicator of typhoid fever. This had a sensitivity of 75%, specificity of 98%, NPV of 100%, but PPV was only 26%. We compared our main findings with those from previous studies.


CONCLUSIONS
Among febrile hospitalized Tanzanian children with a low prevalence of typhoid fever, a Widal titer of > or = 1:80 performed well in terms of sensitivity, specificity, and NPV. However a test with improved PPV that is similarly easy to apply and cost-efficient is desirable.
Ley
Benedikt
B
International Vaccine Institute, Seoul, Korea. bnley@ivi.int
Mtove
George
G
Thriemer
Kamala
K
Amos
Ben
B
von Seidlein
Lorenz
L
Hendriksen
Ilse
I
Mwambuli
Abraham
A
Shoo
Aikande
A
Malahiyo
Rajabu
R
Ame
Shaali M
SM
Kim
Deok R
DR
Ochiai
Leon R
LR
Clemens
John D
JD
Reyburn
Hugh
H
Wilfing
Harald
H
Magesa
Stephen
S
Deen
Jacqueline L
JL
D000293:Adolescent; D000372:Agglutination Tests / Q000379:methods*; D001431:Bacteriological Techniques / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003906:Developing Countries; D006761:Hospitals; D006801:Humans; D007223:Infant; D011237:Predictive Value of Tests; D012424:Rural Population; D012485:Salmonella typhi / Q000276:immunology*; D012680:Sensitivity and Specificity; D013636:Tanzania; D014435:Typhoid Fever / Q000175:diagnosis*