Anyone ever have issues with resistance on your syringe when administering a PPD skin test? I work for a home health agency and do these often and every now and then when I am injecting the serum into the skin it is almost like it won't come out of the syringe. I make sure the plunger isnt stuck prior to even drawing it up. I have to push it in much harder to get it to go and then it goes in very very slow. Just curious.