It typically ranges about 35-50%. But 'normal' is 'relative.'
My daughter came in at 4% ...................... she has 100% success a year later since her dysfunctional gallbladder was removed and she was only 16yrs old.
They told us the lower the #, the higher % chance it will be a success in the symptom dept.
So with a 4% HIDA Scan result, we were told she'd probably have a 96% success rate.
C~