Diagnosing enteric fever: a reappraisal.

The diagnostic value of 19 clinical and laboratory events was assessed in 150 enteric fever cases. A logistic regression analysis revealed only 8 predicitive variables for the presence or absence of enteric fever. These were, in order of importance, the white blood cell count, the S. typhi H agglutinin titre, body temperature, the S. typhi O agglutinin titre, the S. paratyphi A H agglutinin titre, the S. paratyphi B H agglutinin titre, age and the fever pattern. This study showed that objective variables like the Widal titres were useful in predicting enteric fever, whilst symptoms such as abdominal pain were unhelpful. Use of all 8 variables to calculate the probability of enteric fever might provide an accurate method of diagnosing or confirming enteric fever when culture results are unavailable or negative.