Notified bodies should ensure that the conformity assessment activities for high-risk AI systems are carried out in an efficient, professional, impartial and independent manner. They should have appropriate expertise, including in-house expertise, to carry out internal assessments of AI systems, including the assessment of training, testing and validation datasets and processes. Notified bodies should be able to draw on external expertise for certain tasks and should have appropriate internal procedures to manage potential conflicts of interest. The Commission should, after consulting the Board, develop guidelines for the role and functioning of notified bodies, in particular as regards the testing, auditing and certification of AI systems and the fees to be charged by notified bodies.