Sri Ramachandra University, India
Thambarasi Sundaram has completed her MBBS and Post graduation studies from Sri Ramchandra University, India.
Objectives: To determine the usefulness of Typhidot M in rapid diagnosis of typhoid fever in children and to determine the sensitivity and specificity of Typhidot M with blood culture as gold standard.
Methods: Blood samples were collected from 130 children who were clinically diagnosed as typhoid fever. Typhidot-M is a dot enzyme immunoassay for detection of specific IgM to Salmonella Typhi. Samples were serologically tested with Typhidot assay as per the kit instruction (Typhipoint M/s AB diagnopath Mfg. Pvt. Ltd). For analysis purpose study group was divided into four; Confirmed Typhoid fever: Diagnosis of typhoid fever as confirmed by positive culture of S. Typhi; Probable typhoid fever: Children with fever and with a positive serodiagnosis (WIDAL) or antigen detection test but without S. Typhi isolation; Clinical enteric fever: Patient’s whose clinical course is compatible with typhoid fever but without S. Typhi isolation; and Non-typhoid fever: Children with definitive alternative diagnosis and in whom blood culture is negative for Salmonella Typhi.
Results: Of the 130 blood samples, 31 (23.8%) were positive of Salmonella Typhi infection and remaining 99 were negative for Salmonella Typhi. 54 (41.5%) were typhidot IgM positive. There were no cases in which culture was positive and typhidot negative. But there was false positive in 23 patients (17.6%). Of these 5 were probable typhoid fever, 2 were clinical typhoid fever, 3 had infection with S. Paratyphi A and 13 patients in non-typhoid group. The sensitivity, specificity, positive and negative predictive value of Typhidot test in comparison with blood culture were 100%, 76.7%, 57.4%, 100%, respectively.
Conclusions: After analyzing the present study, it was concluded that blood culture remains the gold standard for the diagnosis of typhoid fever. Typhidot M may be an alternative in early and rapid diagnosis of typhoid fever where facility of blood culture is not available.