Although the confirmative diagnosis of typhoid fever is by culture of the causative organism, usually from blood, a serological test is still necessary to provide a more rapid method of diagnosis. The indirect fluorescent antibody test, using a Salmonella typhi Vi antigen and a FITC-conjugated rabbit anti-human polyvalent immunoglobulin, was evaluated for the diagnosis of typhoid fever. Serum specimens were collected from patients with febrile diseases on admission. Of the 32 patients with titers of 1:64 or more, 22 were confirmed to have typhoid fever by blood culture and 7 had fever of undetermined origin that was considered to be typhoid fever clinically. Three patients were diagnosed to have salmonellosis other than typhoid fever. Of the 121 patients with titers of 1:32 or less, 105 patients had non-typhoidal febrile disease, 15 patients had fever of undetermined origin, and one patient was confirmed to have typhoid fever by blood culture. When a Vi antibody titer of 1:64 or more was taken as serological evidence for the diagnosis of typhoid fever, the sensitivity and specificity were 95.7% and 97.2%, respectively. The incidence of positive test results following fever onset was 70.0% within 1 week of fever onset, 88.9% from 1 to 2 weeks, and 100% after 2 weeks. In conclusion, the Vi-indirect fluorescent antibody test(Vi-IFAT) can be employed as a useful serologic test in the diagnosis of typhoid fever.
Antigens, Bacterial/*analysis ; Fluorescent Antibody Technique/*standards ; Human ; Salmonella typhi/immunology ; Sensitivity and Specificity ; Typhoid Fever/*diagnosis

OBJECTIVECompare the difference of the results referred to the WHO standard rabies immunoglobulin and the national standard human rabies immunoglobulin used in the rapid fluorescent focus inhibition test (RFFIT).

METHODSSetting the WHO standard immunoglobulin and the national standard immunoglobulin in the same system and testing 12 human serum at the same time. Compare the fluorescence percentage of the two different standard immunoglobulin; compare the 12 serum results calculated from the two different standard immunoglobulin used the calculation formula of neutralization antibody titer.

RESULTSThe Results display that the 50% percent of the two standard immunoglobulin are all between the fifth and the sixth well, but the percentage of the national standard immunoglobulin is lower than the WHO one. The same testserum result calculated from the WHO standard immunoglobulin is little higher than the national one.

CONCLUSIONThere is difference in the WHO standard immunoglobulin and the national one, but there is no influence in the results.

Fluorescent Antibody Technique ; methods ; standards ; Humans ; Immunoglobulins ; immunology ; Neutralization Tests ; methods ; standards ; Rabies ; diagnosis ; immunology ; Rabies virus ; immunology ; Reference Standards ; World Health Organization