Table 1.

Results of Tests for IgM and IgG Antibodies against the New Ehrlichia Species, Ehrlichia chaffeensis, and Anaplasma phagocytophilum.^*

Patient No.†	Days from Illness Onset to Specimen Collection	Specimen Type	Reciprocal IgM and IgG Titer, CDC Assay						Reciprocal IgG Titer, Mayo Clinic Assay
			New Ehrlichia Species		E. chaffeensis		A. phagocytophilum		E. chaffeensis	A. phagocytophilum
			IgM	IgG	IgM	IgG	IgM	IgG
1	198	Plasma	256	128	256	<16	<16	<16	NA	NA
2	2	Serum	NA	NA	NA	<32	NA	<32	<64	<64
2	15	Serum	512	256	256	64	<16	<16	<64	<64
2	188	Plasma	16	64	<16	32	<16	<16	NA	NA
4	7	Serum	NA	NA	NA	NA	NA	NA	256	<64
4	46	Serum	NA	NA	NA	NA	NA	NA	1024	<64
4	76	Plasma	32	2048	<16	2048	<16	<16	NA	NA

^*Antibody titers were assessed with the use of a noncommercial indirect immunofluorescence assay at the Centers for Disease Control and Prevention and with the use of a commercial indirect immunofluorescence assay (testing for IgG antibody but not IgM antibody) at the Mayo Clinic. NA denotes not available.

^†Specimens from Patient 3 were not available for testing.