Since Physician Assistants (PA) and Advanced Practice Registered Nurses (APRN) are not physicians, are organizations required to credential and privilege them via the requirements found in the Medical Staff (MS) chapter of the accreditation manual?

Any examples are for illustrative purposes only.

Yes, any provider recognized by state law and providing services as a 'Licensed Practitioner (LP)^^ or providing a medical level of care and decision-making(e.g. writing orders, directing care, etc) is required to be granted privileges prior to providing care, treatment or services. While Physician Assistants (PA) are generally not recognized by law/regulation as 'independent practitioners', they are subject to the same credentialing and privileging requirements outlined in the Medical Staff chapter of the manual.  Examples of Care, Treatment or Services subject to the Medical Staff requirements may include, but are not limited to:

The requirements for conducting a Focused Professional Practice Evaluation (FPPE - MS.08.01.01) and an Ongoing Professional Practice Evaluation (OPPE - MS.08.01.03) also apply to these practitioners.  When an Advanced Practice Registered Nurse (APRN) or PA functions in a limited role, such as an educator, and are not directing care as a LIP, the Medical Staff requirements would not apply.
 

^^It is the responsibility of the individual organization to determine, based on law/regulation, if the APRN or PA meet the following definition of a Licensed Practitioner:  "An individual who is licensed and qualified to direct or provide care, treatment, and services in accordance with state law and regulation, applicable federal law and regulation, and organizational policy.