In school I was taught 15mm but on CDC its giving two different answers which can i go by for standard?
Quote from KelRN215
. Remember that a positive PPD only means the patient has been exposed to TB, it doesn't tell you anything about the presence or absence of infection.
Not necessarily true. Recent live vaccination (MMR, VZV, Smallpox) in the last 28 days can cause a false positive. If you also currently have or have very recently had measles or smallpox it can also cause a false positive. It also depends on the age of the person as well, as a child under 6 months might pop a false positive.
Many other countries also vaccinate with the BCG so those individuals *most likely* are going to show positive forever. Best to just get a chest x-ray and/or TB Gold.
Last edit by DowntheRiver on Jun 17
: Reason: ETA: most likely