TABLE 5.

PPVs and NPVs of serology estimated with Bayes's formula for different prevalences of B. henselae bacteremia in cats from six locations in northern Italy

LocationResults
Blood culturePredictive value for serological result
No. of cats examinedPrevalence (P) (probability pretest) (%)PPV (%)Change in probability (PPV-P) (%)Prevalence (1 − P) of Bartonella-free cats (pretest probability) (%)NPV (%)Change in probability NPV − (1 − P) (%)
Milan1145.38.73.494.796.51.8
Brescia568.914.25.391.194.02.9
Pavia4337.250.112.962.872.19.3
Lomellina17814.121.87.785.990.34.4
Oltrepò Pavese29215.724.08.384.389.24.9
Garda Lake environs8648.361.31351.762.110.4