If your chosen faculty had a problem with your turnitin score, believe me, you would already know about it. They all take plagiarism and academic dishonesty very seriously.
A certain percentage on a turnitin score will always occur in any piece of work if you are discussing a particular scientific discipline, because of the use of standardised terminology. For example, if you wrote an essay discussing acute myocardial infarction, there are probably many many phrases and terms very closely associated with that condition that you would virtually have no choice but to type and include and this would cause turnitin to detect similarities with other work as a result.