In our own tests at Consumer Reports, we found that the recommended kits showed no false positives and no false negatives.

NPR: Do Home Lead-Testing Kits Work?

Critics said the prospect of a no-hands T-Ray search raised general privacy concerns and fears over so-called false positives where an object on a person's body could be misread to be a weapon.

WSJ: Police Test New Scanner

According to Sequella, early trials show that the patch picks up 98% of those infected, yields few false positives and is easier to use in the field than tuberculin-testing, since no needles are required.

ECONOMIST: A poor diagnosis