These categories include:
- The care provided by certain clinicians—Some proposed legislation, for example, lists the medical specialties of primary care as family medicine, general internal medicine, general pediatrics, and obstetrics and gynecology. Some experts and groups have included nurse practitioners and physician assistants as part of the Primary Care group.
- A set of activities whose functions define the boundaries of primary care—such as curing or alleviating common illnesses and disabilities.
- A level of care or setting—an entry point to a system that includes secondary care (by community hospitals) and tertiary care (by medical centers and teaching hospitals), ambulatory versus inpatient care.
- A set of attributes, as in the 1978 IOM definition—care that is accessible, comprehensive, coordinated, continuous, and accountable—care that is characterized by first contact, accessibility, longitudinally, and comprehensiveness.
- A strategy for organizing the health care system as a whole—such as community-oriented primary care, which gives priority to and allocates resources to community-based health care and places less emphasis on hospital-based, technology-intensive, acute-care medicine.
No one category incorporates all the dimensions that people believe are denoted by the term, and this has resulted in a lack of clarity and consensus about the meaning of the term. A clue to the difficulty lies in an ambiguity of the word primary. If primary is understood in its sense of first in time or order, this leads to a relatively narrow concept of primary care as "first contact," the entry point, or ground floor of health care delivery. This meaning of primary can connote only a triage function in which patients are then passed on to a higher level of care.
If, on the other hand, primary is understood in its sense of chief, principal, or main, then primary care is better understood as central and fundamental to health care. This latter idea of primary care supports the multidimensional view of primary care envisioned by the Institute of medicine (IOM) committee.
The notion of the primary physician providing continuing and comprehensive care was introduced very early. According to what became known as the Millis Commission report (1966), the primary physician
will serve as the primary medical resource and counselor to an individual or a family. When a patient needs hospitalization, the services of other medical specialists, or other medical or paramedical assistance, the primary physician will see that the necessary arrangements are made, giving such responsibility to others as is appropriate, and retaining his own continuing and comprehensive responsibility.
The report also emphasized the need to focus ''not upon individual organs and systems but upon the whole man, who lives in a complex social setting. …".
From 1966 to the late 1970s variations and refinements of this concept appeared. In a classic monograph, Alpert and Charney (1973) described the three fundamental characteristics of primary medicine (defined as the personal health system of individuals and families, as distinguished from public health):
(1) Provide first-contact care (as compared to that based on referral),
(2) Assume responsibility for the patient over time regardless of the presence or absence of disease, and
(3) Serve as the "integrationist" (serve a coordinating role). They also believed that it was preferable that all family members be cared for by the same physician.
In pathology prevention, as opposed to treatment of existing pathologies, primary medicine requires proactivity, doing things before the pathogens strike. Due to this difference, there are two differing schools of thought, one establishes that the individual maintains the authority and responsibility for primary medicine, the other assigns this authority and responsibility to public health.
At PathologyPrevention, we place this authority and responsibility with the individual, but we also include other professionals on a team of care givers, with the Health Guardian filling the primary role. In this way, we advocate collaborative medicine with no ambiguity of authority and responsibility in the role of primary care.