Diagnosis of typhoid fever by Dot enzyme immunoassay in an endemic region.
OBJECTIVE
To compare the results of Dot Enzyme Immunoassay (EIA) and concomitantly performed blood culture for the diagnosis of typhoid fever.


METHODS
The results of Dot Enzyme Immunoassay (EIA) of patients who also had blood cultures/bone marrow culture performed at the same time were analyzed. The period of study spans between April 1997-September 1997.


RESULTS
A total of 1760 Dot Enzyme Immunoassays were performed from April 1997 to September 1997. Of these, only 128 (7.2%) cases had concomitantly performed blood/bone marrow cultures. Therefore, the study was narrowed down to these 128 cases. Sixty-nine cases were culture positive for S. typhi. Of these culture proven cases, IgM antibodies by Dot EIA were positive only in 49 (71%) cases while 20 (28.9%) of culture proven cases remained negative for IgM antibodies.


CONCLUSIONS
Taking blood/bone marrow culture as gold standard, the sensitivity of Dot EIA was found to be 71% while specificity was found to be 43%. The predictive value of the positive test was found to be 59.7% and that of a negative test was found to be 56.5%.
Khan
E
E
Departments of Pathology and Community Health Sciences, Aga Khan University Hospital, Karachi.
Azam
I
I
Ahmed
S
S
Hassan
R
R
D019353:Endemic Diseases; D006801:Humans; D007124:Immunoenzyme Techniques; D010154:Pakistan / Q000453:epidemiology; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012485:Salmonella typhi / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D014435:Typhoid Fever / Q000175:diagnosis* / Q000453:epidemiology