Typhoid fever and Salmonellosis are epidermic in many pasts of the developing world. The widal test is the most widely used test to demonstrate Salmonella O and H antigens in the patient serum Its ease of use and the unavailability of microbiological facilities to perform blood culture along with the time taken to confirm results has led to the preference of the widal test. This however has led to physicians placing too much reliance on a single widal test. It is essential follow up test are performed to demonstrate a 2-4 fold increase in titre indicative of current infection

If agglutination reaction are observed the following approximate titres would be observed if a confirmatory tube test was carried out : 80 ul. = 1:20 40 ul = 1:40 20 ul = 1:80 10 ul = 1:160 5 ul = 1:320 In this way the rapid slide test provides an approximation to the expected results from a corresponding tube test Note : It is necessary to perform all dilutions in the slides test to obviate the prozone effect where higher concentrations of the serum may give a negative resukt but further dilutions may give a positive result.