A 4-year-old child with suspected enteric fever presents on day 8 of illness with fever >39°C, bradycardia, rose spots, and splenomegaly. Widal test shows O titer 1:160 and H titer 1:80 on a single sample. Blood culture is pending. Which statement about Widal test interpretation is CORRECT?
- A O titer ≥1:80 on single sample is diagnostic of enteric fever in endemic areas
- B H titer is more diagnostic of active infection than O titer
- C A fourfold rise in paired sera (2 weeks apart) is most diagnostically significant; single O titer ≥1:160 in endemic areas is suggestive ✓
- D Widal test becomes negative after antibiotic administration, confirming treatment response
Explanation
The Widal test has significant limitations in endemic areas due to cross-reactions with other enteric organisms and prior immunization with typhoid vaccine. A single O titer ≥1:160 is considered suggestive of recent/active S. typhi infection in endemic settings, but a fourfold rise in paired sera (taken 2 weeks apart) is the most diagnostically significant finding. O antibodies indicate current infection and appear early (week 1); H antibodies appear later and persist longer — elevated H titer may reflect past infection or vaccination. Blood culture (positive in 75–90% in week 1) remains the gold standard. Widal titers may remain elevated for months regardless of treatment.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.