Typhoid Test: Widal vs Typhidot — Which Is More Accurate?

By Dashvanth Healthcare Medical Team · Reviewed by our specialists · East Delhi

The Persistent Typhoid Problem in Delhi

Typhoid fever (Salmonella typhi infection) remains endemic in Delhi despite urban sanitation improvements. Contaminated water and food are the primary sources. Accurate and timely diagnosis is critical — both for appropriate antibiotic therapy and to prevent the spread of fluoroquinolone-resistant typhoid.

Available Tests

Widal Test (Agglutination Test)

• Measures antibodies against Salmonella O and H antigens
• Significant titre: O ≥1:80, H ≥1:160 in Delhi (high-endemicity areas have higher background titres)
• Problems: Poor specificity — cross-reacts with other salmonellae; rises in prior vaccination; borderline results common
• Timing: Positive from Day 6–10 of illness; negative in first week
• Verdict: NOT recommended as sole diagnostic tool — still widely used but unreliable

Typhidot (IgM/IgG ELISA)

• Detects IgM (current infection) and IgG (past exposure/vaccination) antibodies to outer membrane protein of S. typhi
• IgM positive from Day 4–5
• Better sensitivity and specificity than Widal
• Typhidot-M (only IgM) reduces false positives from prior exposure

Blood Culture — GOLD STANDARD

• Confirms diagnosis with 100% specificity
• Best yield in Week 1 of illness (70–80% sensitivity)
• Reports in 48–72 hours
• Provides antibiotic sensitivity data — critical in era of drug resistance

Which Test to Order?

• Days 1–7 of fever: Blood culture (most important) + Typhidot IgM
• After Day 7: Widal may add value but interpret cautiously