
False-positive and false-negative results live in certain group settings, such as prisons, nursing homes, and homeless sheltersįor people without a known risk factor for TB, a 15 mm or larger firm swelling at the injection site indicates a positive reaction.are infants, children, or adolescents who’ve been exposed to high-risk adults.are immigrants who’ve come from a country that’s had a high TB rate in the past five years.have diabetes, kidney failure, or other conditions that increase their TB risk.
#Ppd expenses meaning skin#

A negative result means that you most likely haven’t been infected with the bacteria that cause TB.

If the area of skin where you received the PPD injection isn’t swollen or is only slightly swollen 48 to 72 hours after the injection, the test results are negative.
