TABLE 3

Results of microbiology tests (PCR and IFAa) of all proven, probable, and possible chronic Q fever patients

ResultAll chronic Q fever (n = 284) (n [%])Proven chronic Q fever (n = 151)b (n [%])Probable chronic Q fever (n = 64)d (n [%])Possible chronic Q fever (n = 69) (n [%])
PCR positive in blood only60 (21.1)60 (40)
PCR positive in tissue only25 (8.8)25 (17)
PCR positive in blood and tissue35 (12.3)35 (23)
Phase I IgG titer
    5122 (0.7)2c (1)
    1,02435 (12.3)6 (4)13 (20)16 (23)
    2,04861 (21.5)24 (16)13 (20)24 (35)
    4,09662 (21.8)28 (19)17 (27)17 (25)
    8,19236 (12.7)17 (11)10 (16)9 (13)
    >8,19279 (27.8)66 (44)10 (6)3 (4)
  • a IFA, immunofluorescence assay.

  • b For two patients, no titration for a titer above 4,096 was performed; for three patients, no reliable IFA titer results were obtained due to blood transfusion or fluid supplementation; for three patients, no IFA titer was performed (PCR results in blood and/or tissue were positive), but complement binding reaction (CBR) was performed (PCR results in blood and/or tissue were positive).

  • c One patient with positive PCR for blood, one patient with positive PCR for vascular tissue.

  • d In one patient no titration of serology above 4,096 was performed.