Table 2.

Modified case definitions^* for human granulocytic anaplasmosis (HGA). ⁸²

Case definition	Laboratory test result
Supportive HGA	Morulae present in peripheral blood smear neutrophilsa or
	Single serum A. phagocytophilum IgG titer by IFAb ≥ 640
Confirmed HGA	A. phagocytophilum IFA IgG seroconversion d or
	Positive A. phagocytophilum PCRc of blood or
	Isolation of A. phagocytophilum from bloode or
	A. phagocytophilum antigen present in tissue sample by immunohistochemistry

^*Definitions are dependent upon a presentation with manifestations clinically-consistent with HGA.

^aLight microscopy of Wright stained peripheral acute phase blood;

^bIndirect immunofluorescent antibody test with A. phagocytophilum antigen;

^cPolymerase chain reaction with specific A. phagocytophilum primers;

^dFourfold or greater change in serum antibody titer;

^eIsolation of A. phagocytophilum from blood incubated in HL-60 human promyelocytic cell line.