When a patient with a known diagnosis enters a hospital for a specific minor surgical procedure or other treatment that is expected to keep them in the hospital for only a few hours (less than 24), and this expectation is realized, they are considered an outpatient regardless of: the hour of admission; whether or not they used a bed; and whether or not they remained in the hospital past midnight.

Renal dialysis treatments are usually outpatient services but may be inpatient services. A patient who is staying at their home, who is ambulatory, whose condition is stable and who comes to the hospital for routine, chronic dialysis treatments, and not for a diagnostic workup or a changed in therapy, is considered an outpatient. On the other hand, a patient undergoing short-term dialysis until their kidneys recover from an acute illness (acute dialysis), or a person with borderline renal failure who develops acute renal failure every time they have an illness and requires dialysis (episodic dialysis), is always an inpatient. A patient may begin dialysis as an inpatient and then progress to an outpatient status.

If doubt exists as to a particular patient's status after these criteria are applied, a medical opinion is obtained by the intermediary.

The 1972 Amendments extended coverage to disabled beneficiaries. As a result, beneficiaries in the child-bearing years are included for the first time. Reasonable and necessary services associated with pregnancy are covered and reimbursable under Medicare. The increased possibility of illness or injury which accompanies this condition is well recognized, and medical supervision is required throughout pregnancy and for a brief period beyond. Skilled medical management is appropriate throughout the events of pregnancy, beginning with diagnosis of the condition, continuing through delivery, and ending after the necessary postnatal care. Similarly, in the event of termination of pregnancy, regardless of whether terminated spontaneously or whether abortion is induced for therapeutic or elective reasons, the need for skilled medical management and/or medical services is equally as important as in those cases carried to full term.

After the infant is delivered and is a separate individual, items and services furnished to the infant cannot be covered and reimbursed under the program on the basis of the parent's eligibility.