Interpret Your Widal Test (Typhoid) Results
Enter your Widal value below and get an instant, free AI interpretation — a plain-English explanation checked against WHO/IFCC reference ranges.
Medical Disclaimer
This AI-generated interpretation is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Results may vary based on individual health factors not captured here.
Always consult a qualified healthcare professional before making any health decisions. Read full disclaimer →
Widal Test (Typhoid) Normal Ranges
The Widal test is an agglutination test that detects antibodies (IgM and IgG) against Salmonella typhi and Salmonella paratyphi antigens — specifically the O (somatic/cell wall) and H (flagellar) antigens.
| Reference Range | Unit | Notes |
|---|---|---|
| < 1:80 | titer | O antigen <1:80 considered normal in non-endemic areas; significant ≥1:160 (or ≥1:320 in endemic areas) |
Why Doctors Order the Widal Test (Typhoid) Test
The Widal test is widely used in low-resource settings due to low cost and availability, but its diagnostic accuracy is limited. A single Widal test is unreliable — a fourfold or greater rise in titer between acute (early illness) and convalescent (2–3 weeks later) serum samples is considered significant.
How to Enter Your Widal Result
Enter your Widal value in titer, exactly as shown on your lab report.
What a Low or High Widal Can Be Associated With
Below the reference range
- Early acute typhoid (first 5–7 days — antibodies have not yet developed)
- Typhoid treated with antibiotics before serological response develops
Above the reference range
- Active typhoid fever (Salmonella typhi infection)
- Paratyphoid fever (Salmonella paratyphi A, B, or C)
- Prior typhoid infection (antibodies persist for months to years)
- Typhoid vaccination (whole-cell vaccine induces both O and H agglutinins)
- Cross-reactivity with other Salmonella species and non-typhoidal Salmonella
These are common associations, not a diagnosis. A single result is read alongside your symptoms, history and other tests — discuss it with your doctor.
What Can Change Your Widal Result
Before you read too much into a result, consider whether any of these applied:
- Prior typhoid infection (elevated background titers in endemic areas)
- Typhoid vaccination (whole-cell vaccine causes both O and H titer elevation)
- Cross-reactions with Brucellosis, Rickettsial infections, malaria, and other Gram-negative infections
- Antibiotic treatment before blood draw suppresses antibody response and may cause false-negative Widal
Preparing for the test: Collect acute serum during the first week of illness and convalescent serum 2–3 weeks later for most reliable interpretation. A single titer alone is difficult to interpret.
Symptoms That Often Prompt Widal Testing
- Sustained stepladder fever (rising each day for the first week)
- Headache and generalized malaise
- Relative bradycardia (pulse slower than expected for the fever degree)
- Rose spots (faint salmon-colored rash on the trunk) — seen in <30% of cases
- Abdominal pain and distension, constipation (early) followed by diarrhea (later)
Want the full clinical guide to Widal Test (Typhoid)?
Reference ranges, causes, symptoms, preparation, and FAQs.