An “EM call” can refer to two different things in healthcare, and which one applies depends on the context. In most hospitals, it describes a physician being on call for the emergency department, meaning they’re available to come in and treat patients when needed. In medical billing, “E/M” (short for Evaluation and Management) refers to a category of billing codes that doctors use to get paid for patient visits. Here’s what each term means in practice.
On Call for the Emergency Department
When a specialist physician takes “EM call” or “ED call,” they agree to be available during a set period to respond if the emergency department needs their expertise. A patient might arrive with a complex fracture, a neurological emergency, or a condition that requires a surgeon. The emergency physician stabilizes the patient, then contacts the on-call specialist to come in and provide definitive treatment.
This is different from how emergency physicians themselves work. Emergency medicine doctors typically work scheduled shifts because EDs are open 24 hours a day and require constant staffing. Surgeons, cardiologists, orthopedists, and other specialists, on the other hand, use a traditional on-call model: they may be home or in the office but carry a pager or phone and are expected to respond when the ED pages them.
On-call arrangements vary by hospital. Some compensate specialists at a fixed rate per relative value unit for treating unassigned patients (those without an existing doctor). Faster response times from on-call physicians reduce the average length of stay in the emergency department and can shorten hospital admissions overall. However, the American College of Emergency Physicians has noted that specialized treatment sometimes isn’t available because on-call doctors won’t come in when called, won’t volunteer for call duty, or simply aren’t available in the area.
How On-Call Shifts Work in Training
For medical residents, being on call follows rules set by the Accreditation Council for Graduate Medical Education (ACGME). Residents are limited to an 80-hour work week averaged over four weeks, with a 24-hour on-duty limit (plus a 6-hour extension for patient continuity). In-house call can’t happen more than every third night, and residents must get at least 10 hours of rest between clinical duty periods.
Many training programs have moved to a “night float” system instead of traditional overnight call. In this setup, a resident comes in around 7 p.m. and works until 7 a.m., then goes home. This replaces the older model where a resident would work a full day, stay overnight on call, and sometimes continue into the next day. Emergency medicine residencies lean heavily on shift-based scheduling rather than traditional call because of the unpredictable, high-acuity nature of ED work.
E/M in Medical Billing
In billing and coding, “E/M” stands for Evaluation and Management. These are the codes healthcare providers use when billing insurance for patient visits, whether in an office, hospital, or emergency department. If you’ve ever seen a charge on a medical bill labeled with a code starting in “992,” that’s an E/M code.
Historically, E/M billing was built on three components: the patient’s history, the physical examination, and the complexity of the medical decision-making involved. A straightforward visit (like a follow-up for a stable condition) would bill at a lower level, while a complex visit involving multiple diagnoses and significant risk would bill higher.
Major reforms rolled out in 2021 for office visits and expanded across all settings in 2023. The American Medical Association and the Centers for Medicare and Medicaid Services eliminated the requirement to document a detailed history, physical exam, and review of systems just to justify a billing level. Now, providers select a code based primarily on the complexity of their medical decision-making or the total time spent on the encounter. The goal was to cut down on paperwork that didn’t improve patient care.
When a Covering Doctor Sees You
If you’re a patient and your regular doctor isn’t available, a covering physician may see you instead. Under current coding guidelines, the visit is billed the same way it would have been if your own doctor had been there. The covering doctor doesn’t bill at a different rate or under different rules simply because they’re filling in. This applies in offices, hospitals, and emergency departments alike. From your perspective as a patient, the visit and the billing should look essentially the same regardless of which physician is on call.