The CHT credential is the highest professional certificate that can be given to a therapist who specializes in upper extremity treatment and rehabilitation. Occupational therapists who wish to gain the CHT credential are required to have a minimum of three years of clinical experience and 4,000 hours of direct practice in hand therapy. Once these requirements are met, they must complete a comprehensive exam which tests their superior clinical skills and theory in upper extremity rehabilitation. Each certified hand therapist must recertify every five years to show they have maintained and expanded their advanced knowledge and skillset.