Initial clinical findings:
(1) tick exposure or tick bite
(2) acute febrile illness with temperature > 37.6°C
(3) unrevealing physical examination
Screening tests:
(1) CBC count with differential count of peripheral blood and smear review
(2) C-reactive protein levels (CRP)
Findings in screening tests - one or more of the following:
(1) leukopenia (WBC count < 4,500 per µL, page 556)
(2) thrombocytopenia (platelet count < 150,000 per µL)
(3) elevated C-reactive protein (CRP)
(4) morulae within leukocytes in the peripheral blood smear
If one or more findings are present in the screening tests, then perform a specific blood test:
(1) indirect fluorescent antibody (IFA) testing, with convalescent testing after 2-4 weeks.
(2) PCR analysis
(3) cell culture of blood sample
Once blood for specific tests has been collected, start therapy with doxycycline.
If findings absent, then observe the patient for 24 hours.
(1) If the patient's clinical condition deteriorates, then repeat screening tests.
(2) If the patient's clinical condition improves, then observe until illness resolves.
