Table 4.

Cutoff proposal for Q fever diagnosis by using microimmunofluorescence and interpretation of serological results obtained with a single serum sample

Phase II antibody titerPhase I antibody titer (IgG)Interpretation
IgGIgM
≤100Active Q fever improbable
≥200≥50Acute Q fever (100% predictive)
≥1:800Chronic Q fever (98% predictive)
≥1:1,600Chronic Q fever (100% predictive)