Evaluation of Nucleic Acid Amplification Method in Diagnosing Enteric Fever in Children

Abstract

The comparison of three detection methods (Widal test, Typhi dot and Nested PCR) for diagnosis of typhoid fever was done in laboratory where gold standard was either Widal positive or Typhi dot positive or both positive. A nested polymerase chain reaction (PCR) specific for Salmonella enteric serovar typhi was used for the detection of the pathogen in blood samples. Total 52 patients with clinical suspicion of typhoid fever were recruited in the study. Only five patients were gold standard positive and 18 patients were nested PCR 18 positive. Sensitivity of nested PCR was 100% and specificity was PCR = 35.3%. Widal and PCR showed 100% co-positivity. Sensitivity and specificity of PCR were 100% and 73.5%. PCR showed 40% co-positivity with Typhi dot with sensitivity and specificity 40% and 70%, respectively.