From the Guidelines
Bone marrow culture is the most sensitive method for diagnosing typhoid fever.
Diagnostic Methods for Typhoid Fever
- Bone marrow culture: has a higher sensitivity than blood culture for diagnosis of invasive nontyphoidal Salmonella enterica infection, and is likely to be more sensitive than blood culture for diagnosis of typhoid fever 1
- Blood culture: has a sensitivity of approximately 50% compared with bone marrow culture, and is recommended as the routine practical conventional diagnostic and for the initial diagnostic assessment in people with suspected enteric fever or invasive salmonellosis 1
- Stool and urine cultures: become positive after the first week of symptoms onset, and have a lower sensitivity than blood culture 1
- Serologic tests: should not be used to diagnose enteric fever due to poor performance characteristics 1
Best Practice for Diagnosis
- Blood cultures should be performed in all people with signs of septicemia and when enteric fever is suspected, and should be collected prior to administration of antimicrobial agents to maximize sensitivity 1
- Two to three 20-mL blood cultures are adequate for detection of bacteremia in adults, and lower volumes may be sufficient for detection in infants and children 1
- Continuously monitored blood culture systems may shorten the time to detection and improve sensitivity compared with manual blood culture methods 1
From the Research
Diagnostic Methods for Typhoid Fever
The most sensitive method for diagnosing typhoid fever is a topic of interest in the medical field. Several studies have compared the sensitivity of different diagnostic methods, including:
- Bone marrow aspirate culture (BMAC)
- Blood culture
- Rectal swab culture
- Reverse transcription loop-mediated isothermal amplification (RT-LAMP)
- Nested PCR
Sensitivity of Diagnostic Methods
The sensitivity of these methods has been compared in various studies:
- A study published in 1986 found that BMAC (92%) was significantly more sensitive than blood culture (62%), streptokinase clot culture (51%), and rectal swab culture (56%) 2.
- A systematic literature review published in 2016 estimated that bone marrow culture detected 96% of true positive S. Typhi cases, while blood culture detected 61% 3.
- A prospective study published in 1991 found that bone marrow culture (59%) was more sensitive than blood culture (44%) for diagnosing typhoid fever 4.
- A study published in 2015 found that RT-LAMP was more sensitive than blood culture and rRT-PCR for detecting Salmonella Typhi in blood and fecal samples 5.
- A study published in 2021 found that nested PCR was more sensitive than blood culture for diagnosing typhoid fever, with a detection rate of 28.5% compared to 8% for blood culture 6.
Comparison of Diagnostic Methods
The studies suggest that bone marrow aspirate culture is the most sensitive method for diagnosing typhoid fever, followed by molecular methods such as RT-LAMP and nested PCR. Blood culture, while commonly used, has a lower sensitivity compared to these methods 2, 3, 4, 5, 6.