Each proctoring business has its own requirements. Emed requires the Binax Now test you must purchase through them or Celebrity. This company has been the most reliable and consistent. However, I have read of tests ruled invalid because of broken box seals, liquid vials being empty, and no adhesive on the card that folds over the swab. And you can't open the box to verify the contents are intact. The company will replace the invalid test at no charge. Whatever testing company you decide to use, bring at least two tests per person with you. At over $25.00 per test, and eight in our group, I am leaning away from emed/celebrity testing. Onpoint-testing is also a much used vendor. Any USA test can be used. Just bring extras.