In an asymptomatic patient whose Widal titre has risen from 1:160 to 1:320 over 15 days, should anti‑typhoid therapy be started?

Management of Rising Widal Titre in an Asymptomatic Patient

Do not initiate anti-typhoid therapy in this asymptomatic patient with rising Widal titres alone, as the Widal test has poor specificity and positive predictive value (5.7%), and treatment decisions must be based on clinical presentation and blood culture results, not serological titres. 1

Why the Widal Test Cannot Guide Treatment Decisions

• The Widal test should not be used for diagnosis of enteric fever due to poor performance characteristics, with specificity of only 68.44% and very poor positive predictive value of 5.7% 1
• Blood cultures remain the gold standard for diagnosis, not the Widal test 1
• Rising titres from 1:160 to 1:320 can occur in healthy individuals from endemic areas, with up to 29% of healthy adolescents showing O titres ≥1:40 and 76% showing H titres ≥1:80 in endemic regions 2
• False positives are more common than false negatives with the Widal test, making it unreliable for treatment decisions 3

Critical Clinical Context Required

• Typhoid fever presents with fever in 97-100% of cases 4
• The absence of fever, abdominal pain, or any constitutional symptoms (malaise, headache, anorexia) makes active typhoid fever highly unlikely 4, 5
• The typical incubation period is 7-18 days, and symptoms develop gradually over 3-7 days rather than remaining absent 4, 5

Appropriate Next Steps

• Obtain blood cultures if any clinical symptoms develop, as they have the highest diagnostic yield (40-80% sensitivity) within the first week of symptom onset 1
• Monitor for development of fever, headache, malaise, anorexia, or abdominal symptoms over the next 1-2 weeks 4, 5
• Do not start empiric antibiotics based solely on serological findings in an asymptomatic patient 1

When to Initiate Treatment

• Start empiric treatment only if the patient develops clinical features of sepsis, documented fever ≥38.5°C, or signs of severe illness 4
• If treatment becomes necessary, azithromycin 500 mg once daily for 7 days is the preferred first-line therapy for adults, given widespread fluoroquinolone resistance exceeding 70% in endemic regions 1
• For severe cases requiring IV therapy, ceftriaxone 1-2g IV/IM daily for 5-7 days is recommended 1

Common Pitfall to Avoid

• Never rely solely on the Widal test for diagnosis or treatment decisions—it has poor positive predictive value and should be supplemented with blood cultures and clinical assessment 1
• The clinical picture is the decisive factor in making a diagnosis of typhoid, not serological titres alone 3
• In endemic areas, healthy individuals commonly have elevated antibody titres due to previous exposure, making single Widal tests virtually useless for diagnosis in adolescents and adults 2