sneezydiva

Supposedly, you don't need to stop the antihistimine before the test, but my doctor had me not take it the night before. But assuming the test is correct, I think you should ask your doctor to order a CT scan of your sinuses. You might have an infection that's causing the Post nasal drip. Don't let your doctor tell you since you have no other symptoms that it can't be an infection. I had no other sinus symptoms either, when my allergist suspected an infection because I had chronic brochitis. I ended up needing sinus surgery.