Tests
1st tests to order
CBC
Test
Order if tularemia is suspected. May reveal leukocytosis or thrombocytopenia.[15] Normal results do not rule out the diagnosis.
Result
leukocytosis; thrombocytopenia
serum electrolyte levels
Test
Order if tularemia is suspected. May reveal hyponatremia.[15] Normal results do not rule out the diagnosis.
Result
hyponatremia
LFTs
Test
Order if tularemia is suspected. May reveal elevated transaminases.[15] Normal results do not rule out the diagnosis.
Result
elevated
serum creatine kinase
Test
Order if tularemia is suspected. May reveal elevated creatine kinase in cases complicated by rhabdomyolysis.[15] Normal results do not rule out the diagnosis.
Result
elevated
urine dipstick for blood
Test
Order if tularemia is suspected. May reveal elevated myoglobinuria in cases complicated by rhabdomyolysis. Sterile pyuria may be noted.[15] Normal results do not rule out the diagnosis.
Result
myoglobinuria; leukocytes
erythrocyte sedimentation rate
Test
Order if tularemia is suspected. May reveal elevated erythrocyte sedimentation rate.[15] Normal results do not rule out the diagnosis.
Result
elevated
serology
Test
Order if tularemia is suspected. Diagnostic for tularemia. Enzyme immunoassay (EIA) or immunofluorescence assay (IFA) may be used.[15]
Increase in antibody titer usually occurs 2 to 3 weeks after onset of symptoms.[15]
Result
4-fold rise in serum antibody against Francisella tularensis between acute and convalescence serums
blood culture
Test
Order if tularemia is suspected. Culture is optimal for diagnosis, but can be challenging as F tularensis is slow growing.[15]
Although modern blood cultures (nonradiometric) detect bacteria, this is an insensitive test as bacteremia is only transient.[1] Blood cultures are often negative.[15]
Result
positive for Francisella tularensis
specimen culture
Test
Order if tularemia is suspected. Culture is optimal for diagnosis, but can be challenging as F tularensis is slow growing.[15]
May be cultured from clinical specimens (e.g., lymph node aspirate, ulcer scraping, pharyngeal swab, or respiratory specimens, depending on the type of illness) using special media.[15]
Culture must be performed under biosafety level 3 conditions because of infection risk to laboratory personnel.
Result
positive for Francisella tularensis
polymerase chain reaction (PCR) of ulcer swab or lymph node aspirate
Test
Experience in the use of PCR is limited, but it seems to be a sensitive technique.[1]
Result
positive amplification of Francisella tularensis DNA
Tests to consider
chest x-ray
Test
Ordered when pneumonic tularemia is suspected (indicated by respiratory signs and symptoms). Can show lobar or subsegmental infiltrates or exudative pleural effusions.[4][7][8][9][10][11]
Infiltrates may also be present in typhoidal tularemia in the absence of respiratory symptoms.[15]
Result
segmental or lobar infiltrates or exudative pleural effusions
lumbar puncture
histopathology
Test
Histopathology should be ordered; however, the test is limited by the fact that caseating granulomas are not specific for tularemia, as they can be seen with other infectious and inflammatory conditions.
Result
caseating granulomas in involved tissue
Emerging tests
antigen detection in urine
Test
Current methods of antigen testing in urine have proved insensitive for the detection of F tularensis, and further investigations are needed before it is established as a diagnostic tool.
Result
positive antigen test for Francisella tularensis
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