Suggested approach to diagnosis in the setting of suspected babesiosis infection

PCR: polymerase chain reaction.
* The diagnosis of babesiosis should be suspected in patients with typical clinical manifestations (fever, fatigue, chills, sweats, headache, myalgia, arthralgia, and/or anorexia) and laboratory features (hemolytic anemia, thrombocytopenia, and/or elevation of aminotransferases) in the setting of relevant epidemiologic exposure (eg, residents of endemic areas, travelers returning from endemic areas, or blood transfusion in the previous six months). The diagnosis should also be suspected in patients with Lyme disease, human granulocytic anaplasmosis, or other Ixodes tickborne infections (since the causative agents of these infections are transmitted by the same vector as babesiosis). Refer to the UpToDate topic on diagnosis of babesiosis for further discussion.
¶ The level of parasitemia may be low initially and rise subsequently during the course of illness; therefore, it is reasonable to repeat smears every 12 to 24 hours for a total of at least three smears.