Investigations
1st investigations to order
FBC
Test
Leukopenia and thrombocytopenia occur, but are neither universal nor diagnostic, and may occur in other tropical diseases such as dengue and malaria.
Result
WBC: low to normal; haemoglobin: mild anaemia; platelets: low to normal
serum transaminases
Test
Mild liver function abnormalities are common, with transaminase levels often 2 to 3 times the upper limit of normal.
Clinical jaundice is uncommon.
Result
2 to 3 times upper limit of normal
blood culture
Test
Blood culture sensitivity varies widely between 40% and 87%.[58][59]
May be negative if patients have started antibiotics.
The optimum time for blood culture is considered to be in the first or second week of the illness, although cultures can still remain positive in the third week in the absence of antimicrobial exposure.[57]
Result
positive
stool culture
Test
Stool culture may occasionally be positive even when blood culture is negative, especially if it is taken more than 1 week after the beginning of the fever.
Positive stool gives a presumptive diagnosis. With compatible clinical presentation, especially in returning travellers, it makes the diagnosis very likely.
Result
positive
urine culture
Test
The organism may sometimes be cultured from the urine, although sensitivity is low.
Result
positive
bone marrow culture
Test
Should be considered in patients who have already started antibiotic treatment.
Result
positive
drug susceptibility testing
Test
Antimicrobial susceptibility testing is needed for all confirmed infections to guide treatment.
Result
drug sensitivities
Investigations to consider
rose spot culture
Test
The organism may also be cultured from biopsy tissue from the rose spots, where visible.[Figure caption and citation for the preceding image starts]: Rose spots on the chest of a patient with typhoid feverCDC/Armed Forces Institute of Pathology, Charles N. Farmer; used with permission [Citation ends].
[Figure caption and citation for the preceding image starts]: Rose spots on abdomen of a patient with typhoid feverCDC/Armed Forces Institute of Pathology, Charles N. Farmer; used with permission [Citation ends].
Result
positive
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