Diagnosis & Tests

• Positive blood culture for S. typhi during the first 10 days (90%); fewer than 30% are positive at the end of the third week
• Positive bone marrow culture for S. typhi occurs even when blood cultures are negative.
• Positive stool culture for S. typhi after 10 days, especially during third to fifth week (85%); stool culture may remain positive for more than 1 year in 3% of patients, who are termed chronic enteric carriers. The bacilli are harbored in the gallbladder.
• Positive urine culture for S. typhi during third to fourth week (25%)
• Leukopenia - 4000/ul - 6000/ul in first two weeks; 3000/ul - 5000/ul in second two weeks
• Normochromic, normocytic anaemia - chronic-disease type
• Proteinuria during febrile period
• No increase in sedimentation rate
• Serologic tests are nonspecific.