JerseyTaughtMe - You can relax after you finish reading my reply. Your nurse seems to know what is correct even though she did not give you a clear explanation of what's positive (+) and what's negative.(-) when the TB (also called Tine test or tuberculin injection) is done. All injections, done only with killed material not infectious) produces some redness and a little rise which are negative. A positive is determined NOT by looking but rather by gently feeling for a slightly hardened lump of a minimum size that is felt. Millions of people get a positive in early years which remains positive for life but is okay for working in a hospital. The concern comes, as with your mom, when the test was negative last year and now becomes positive a year later. That would indicate a recent infection and require further testing (like a chest x-ray). OK, now relax and gently breathe out. Thanks very much for volunteering to help others at a hospital.
a medical professional