Widal Test (Definitive/True Test for Typhoid Fever)

The Widal Test (Definitive True) at Pamel Laboratories is a serological test used to detect antibodies (agglutinins) in a patient’s blood that are produced in response to Salmonella typhi and Salmonella paratyphi A, B, and C infections — the bacteria responsible for typhoid and paratyphoid fever.

This version of the test is conducted using standardized antigen suspensions and follows strict interpretation criteria to ensure greater accuracy and specificity, helping to distinguish true typhoid infections from false positives due to prior vaccinations or unrelated infections.

What the Test Detects:

• O antibodies (against somatic antigens of S. typhi)

• H antibodies (against flagellar antigens of S. typhi)

• AH & BH antibodies (against S. paratyphi A & B)

The presence of significant titers or a fourfold rise in titers in paired samples indicates active typhoid or paratyphoid infection.

Purpose of the Test:

• Detect and confirm current or recent typhoid/paratyphoid fever

• Differentiate true infection from past exposure or vaccination

• Aid in the diagnosis of prolonged fever with gastrointestinal symptoms

• Monitor response to antibiotic therapy

Sample Type: Blood sample (serum)

Turnaround Time: Within 24 hours

Important Notes:

• For definitive results, this test may be compared with a follow-up sample after 7–10 days (paired titers)

• Best used in conjunction with clinical evaluation and culture tests (e.g., stool or blood culture) for high diagnostic accuracy

• Not suitable as the sole basis for diagnosis — positive results must be interpreted in clinical context