The document discusses the referral process in healthcare. It defines referral as sending a patient to another practitioner or program for treatment that cannot be provided by the referring source. The referral system aims to improve patient health by providing diagnostic and specialist services. Patients are selected for referral based on their condition and treatment needs. The referral process follows principles like being timely, coordinated, and incorporating patient preferences. The document outlines the different levels and types of referrals as well as components of an effective referral like infrastructure, services, and equipment at first referral units. Barriers to referral services are also acknowledged.