title: Validation of the Dri-Dot Latex agglutination and IgM lateral flow assays for the diagnosis of typhoid fever in an Egyptian population.
abstract: Laboratory confirmation of typhoid fever is essential for appropriate medical treatment. Blood culture is a standard test for diagnosis of typhoid fever, but well-equipped diagnostic facilities to perform culture are seldom available in endemic areas. We retrospectively compared 2 diagnostic field tests, a latex agglutination Dri-Dot assay and an IgM Lateral Flow assay, to blood culture, in patients with clinically diagnosed typhoid fever. Sensitivity of the Dri-Dot was 71.4%, and specificity was 86.3% for samples collected at time of first diagnosis. Sensitivity and specificity of IgM Lateral Flow were 80% and 71.4%, respectively. A major limitation of these serologic tests is the limited sensitivity at the early stage of the disease. Performing both tests in parallel increased sensitivity to 84.3%, but decreased specificity to 70.5%. There was a trend towards improved diagnostic performance using either assay over a longer duration of illness. These rapid, point-of-care assays for typhoid fever provide easy-to-interpret results in typhoid-endemic countries and may be most useful in patients presenting 1 week after symptom onset.
authors.affiliation: US Naval Medical Research Unit No. 3, FPO AE 09835 Box 5000 Cairo, Egypt. isabelle.nakhla.eg@med.navy.mil
authors.forename: Isabelle
authors.initials: I
authors.lastname: Nakhla
authors.forename: Hanan
authors.initials: H
authors.lastname: El Mohammady
authors.forename: Adel
authors.initials: A
authors.lastname: Mansour
authors.forename: John D
authors.initials: JD
authors.lastname: Klena
authors.forename: Khaled
authors.initials: K
authors.lastname: Hassan
authors.forename: Yehia
authors.initials: Y
authors.lastname: Sultan
authors.forename: Rob
authors.initials: R
authors.lastname: Pastoor
authors.forename: Theresia H
authors.initials: TH
authors.lastname: Abdoel
authors.forename: Henk
authors.initials: H
authors.lastname: Smits
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D019411:Clinical Laboratory Techniques / Q000379:methods*; D004534:Egypt; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007075:Immunoglobulin M / Q000097:blood*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014435:Typhoid Fever / Q000175:diagnosis*
chemical_list: D000907:Antibodies, Bacterial; D007075:Immunoglobulin M