Table 3.

Worst-case scenario: validity of chickenpox history, discounting insufficient IgG and counting equivocal as positive.

	VZV IgG Result				Total
	Positive or equivocal		Negative
	n	% [95% CI]	n	% [95% CI]	n
Chickenpox history
Positive	110	94.0% [89.7–98.4%]	7	6.0% [1.6–10.3%]	117
Negative	54	80.6% [71.0–90.2%]	13	19.4% [9.8–29.0%]	67
Uncertain	42	89.4% [80.4–98.3%]	5	10.6% [1.7–20.0%]	47
Negative or uncertain	96	84.2% [77.5–91.0%]	18	15.8% [9.0–22.5%]	114

p-Values for comparison of proportions were calculated as follows: positive vs. negative: p = 0.007; positive vs. negative or uncertain: p = 0.020; positive vs. uncertain: p = 0.327; negative vs. uncertain: p = 0.297.