Widal Test – Typhoid Fever Screening

The Widal Test is a serological test used to detect antibodies against specific antigens associated with Salmonella Typhi and Salmonella Paratyphi. These bacteria can cause enteric fever, commonly known as typhoid or paratyphoid fever.

The test measures antibody reactions against O and H antigens and may be used as part of a clinical evaluation when enteric fever is suspected.

What Does the Widal Test Assess?

• S. Typhi O Antibody: Measures antibodies against the somatic O antigen.
• S. Typhi H Antibody: Measures antibodies against the flagellar H antigen.
• S. Paratyphi Antibodies: Depending on the test panel, may include AH and BH antigen reactions.
• Antibody Titres: Results may be reported as titres, depending on the laboratory method.

Why Is the Widal Test Recommended?

A healthcare professional may request this test to support the investigation of:

• Persistent fever with suspected enteric fever
• Clinical symptoms consistent with typhoid fever
• Possible exposure to enteric fever
• Other findings requiring further diagnostic evaluation

Sample Requirements

• Sample type: Blood, typically serum.
• Fasting: Usually not required.
• Preparation: Follow your healthcare professional’s instructions.

Understanding Your Results

Widal results may be reported as reactive or non-reactive, or as antibody titres. Interpretation depends on local baseline titres, the patient’s symptoms, the timing of the illness, and the laboratory’s validated method.

False-positive and false-negative results can occur. A single Widal result cannot reliably confirm or exclude typhoid fever. Blood culture, preferably collected before antibiotics when feasible, is generally more useful for confirming the diagnosis.

Book Your Widal Test

Choose a convenient diagnostic testing service for laboratory evaluation and professional reporting.

One Family. One Lab. One Health Journey.