Table 1.

Potential outcomes of screening tests with varying levels of sensitivity and specificity

Test characteristic	High sensitivity	High specificity
Impact on results	↑ True positives	↑ True negatives
Testing goal	Identify people with disease	Identify people without disease
Treatment goal	· Treat disease	· Avoid unnecessary treatment
	· Prevent future illness and, in the case of infection, possible disease spread
Potential harms of opposite test characteristic	Low sensitivity:	Low specificity:
	· ↑ False negatives	· ↑ False positives
	· ↑ Potential future illness and suffering	· ↑ Bodily harms, toxicity, and financial costs of unnecessary treatment
	· ↑ Potential future spread of disease (in the case of infection)	· ↑ Social stigmatization
		· ↓ confidence in screening program