Table 3.

Specificities, Sensitivities, and Negative and Positive Predictive Values of Attributing Risk of Exposure Based on 76 Acutely Infected Mothers of Children Enrolled in National Collaborative Chicago-based Congenital Toxoplasmosis Study

	Specificitya	95% CI	Sensitivityb	95% CI	NPVc	95% CI	PPVd	95% CI
At least 1 cat risk factor	24	7–50	69	56–81	18	5–40	76	62–87
	(4/17)		(41/59)		(4/22)		(41/54)
At least 1 significant cat risk factore	71	44–90	49	36–63	29	16–45	85	69–95
	(12/17)		(29/59)		(12/42)		(29/34)

Abbreviations: CI, confidence interval; NPV, negative predictive value; PPV, positive predictive value.

^aSpecificity indicates the percentage of individuals negative for sporozoite antibody who did not identify any cat risk factors.

^bSensitivity is the percentage of persons positive for antibody who identified at least 1 cat risk factor.

^cNPV is the percentage of persons not identifying any risk factors who were negative for antibody to the 11-kDa sporozoite protein.

^dPPV is the percentage of persons identifying a risk factor who were positive for antibody to the sporozoite protein.

^eSignificant cat exposure is defined in Methods as cleaning a cat's litter box, gardening, coming into contact with a sandbox, or very close, sustained contact with a kitten. Owning an indoor cat fed dry or canned food is considered a risk factor associated with cats, but not necessarily one that has substantial risk for exposure to oocysts for the cat owner.