English Proficiency?

I am a US citizen, in a british education system in the United Arab Emirates. I have taken 10 IGCSE’s, among them First language English as well as English literature, both with an A grade. I have also taken the ACT and have achieved a 34 in the English test. Do I need to take any English proficiency examinations? If so, is there another way to demonstrate proficiency as it is too late to submit scores before the deadline.