If you grew up outside the US, you might have that small round scar on your upper arm. That scar usually comes from the BCG vaccine, which is given in many countries with higher tuberculosis rates. The US does not routinely give BCG because tuberculosis is less common here, and strong public health systems focus on testing and treatment instead. Here is the part that surprises people, the BCG vaccine can make your tuberculosis skin test come back positive years later. A positive skin test does not always mean you have active tuberculosis, it just means your immune system remembers the vaccine. When that happens, the next step is usually a Quantiferon blood test or an IGRA test to confirm what is really going on. This is your reminder not to panic if you had BCG as a child and your test is positive. Talk to your doctor and get the right follow up testing. POLL: Do you have a BCG scar? #tuberculosis #bcgvaccine #immigrant #doctor