Widal Test (Salmonella Agglutinins), Serum


The diagnosis of typhoid fever on clinical grounds is difficult, as the presenting symptoms are diverse and similar to those observed with other febrile illnesses. The definitive diagnosis of typhoid fever requires the isolation of Salmonella enterica serotype Typhi from the patient. This bacteria can be isolated from blood in 73-97% of cases before antibiotic use. However, in cases where patients have uncontrolled access to antibiotics, serological analysis becomes important. The Widal tube agglutination test is used in the serologic diagnosis of typhoid fever.


High anti H and anti O antibody titres are suggestive of a positive diagnosis of typhoid fever. However, in certain parts of the world where there is high prevalence of typhoid fever, high H or O antibody titres are found in a proportion of healthy individuals. Therefore, the demonstration of rising H and/or O antibody titres is more reliable in the diagnosis of infection.

Sample Type, Quantity & Conditions

2 ml Serum Room Temperature

Special Precautions

Normal Range

S. typhi O: Negative< 1/40 Titre S. typhi H: Negative < 1/40 Titre S. paratyphi AO: Negative < 1/40 Titre S. paratyphi BO: Negative < 1/40 Titre S. paratyphi CO: Negative < 1/40 Titre S. paratyphi AH: Negative < 1/40 Titre S. paratyphi BH: Negative < 1/40 Titre S. paratyphi CH: Negative < 1/40 Titre A disclaimer is added.

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