Evaluation & Management (E/M) Codes Explained for Coders

Evaluation and Management codes — E/M codes — are the most-used codes in all of outpatient medical billing. Every office visit, every hospital admission, every emergency department encounter generates one. On the CPC exam, E/M coding accounts for roughly 15-20% of the 100 questions, and unlike a CPT index lookup, you can’t just find the answer by flipping to a code range — you have to read a clinical scenario and reason your way to the correct level. This guide walks through how E/M codes are organized, how the 2021/2023 guidelines changed level selection, and how to apply that framework to real documentation.

What Are E/M Codes?

E/M codes describe a physician’s or other qualified healthcare professional’s cognitive work — evaluating a patient, weighing diagnostic possibilities, and deciding on a treatment plan. They sit in the 99202-99499 range of the CPT codebook, separate from the Surgery, Radiology, and Pathology sections, because they capture thinking and decision-making rather than a procedure performed on the body.

That distinction matters for coding logic. A CPT code for an appendectomy describes one specific operation with a fixed global package. An E/M code describes a visit, and the same code can be billed for wildly different patients on different days — the level depends entirely on how complex that particular encounter was.

E/M codes cover far more than office visits: hospital admissions, nursing facility visits, home and residence visits, emergency department encounters, critical care, and preventive medicine exams all have their own E/M code families, each with its own rules.

New Patient vs. Established Patient

The first fork in outpatient E/M coding is whether the patient is new or established to the practice. This isn’t about whether the patient has ever met that specific physician — it’s about the group practice and specialty.

📌 CPC Exam Tip: The three-year rule is measured against the group practice and specialty, not the individual doctor. If a patient saw Dr. Lee (cardiology) at a clinic two years ago and is now seeing Dr. Patel (also cardiology) at the same clinic, the patient is established — even though they’ve never met Dr. Patel. This trips up candidates who read “new doctor” in a scenario and assume “new patient” without checking the specialty and timeframe.

New patient visits pay more than established visits for a comparable level, because the physician has to build a complete history rather than update an existing one — which is why getting this classification right changes the code, not just the documentation.

Office and Outpatient E/M Codes: 99202-99215

99211 is the one code in this range with no MDM or time requirement — it doesn’t even require the physician to be present. It’s used for a brief service performed by clinical staff under physician supervision, such as a blood pressure check or a wound-dressing change for an existing patient.

For every other office/outpatient E/M code, the 2021 guidelines (still in effect for the CPC exam) eliminated the old history/exam/MDM bullet-counting system entirely. Level selection now comes from one of two paths: Medical Decision Making, or Total Time.

Medical Decision Making (MDM): The Three Elements

MDM level is set by the highest two of these three elements:

1. Number and complexity of problems addressed at the encounter
2. Amount and/or complexity of data reviewed and analyzed
3. Risk of complications and/or morbidity or mortality of patient management decisions

The “highest two of three” rule means a visit doesn’t need all three columns to match. A patient with one chronic illness that’s stable (low problem complexity) but who needs a new prescription with risk of side effects requiring monitoring (moderate risk) and a review of recent labs (limited-to-moderate data) could land at moderate complexity on risk and data alone, even though the problem column reads low.

📌 CPC Exam Tip: Don’t average the three columns — find where two of the three meet or exceed a given level. Exam questions are often built specifically to test whether you’ll incorrectly average instead of applying the “2 of 3” rule.

Clinical example: A 58-year-old established patient returns for follow-up of type 2 diabetes mellitus (E11.9) and hypertension — two chronic, stable conditions — with no medication changes and no new labs ordered. Problems: moderate (two stable chronic conditions counts as moderate under the 2021 table). Data: minimal (nothing reviewed or ordered). Risk: low (no medication changes). Two of the three columns — problems and the moderate/low mix on risk — land this visit at low-to-moderate; most coders would select 99213 here on a straightforward read, since data stayed minimal and risk stayed low even though one problem element pushed higher. This is exactly the kind of scenario the exam uses to test whether you apply the table mechanically or actually weigh the elements.

Time-Based Coding: The Total Time Alternative

Instead of MDM, a physician may select the level based on total time spent on the date of the encounter. This includes the face-to-face visit plus non-face-to-face work done that same day: reviewing records before the visit, ordering and interpreting tests, coordinating care, and documenting in the chart.

When time exceeds the top of a level’s range, the add-on code +99417 (prolonged office or outpatient E/M service, each additional 15 minutes) can be reported alongside 99205 or 99215 — the only two base codes it attaches to. Medicare uses its own equivalent HCPCS code, G2212, instead of +99417, with a slightly different time threshold for when it can first be billed — a detail worth double-checking against payer-specific guidance in practice, even though the exam typically tests the CPT version.

📌 CPC Exam Tip: Time-based coding only works for codes that list a total-time range in their descriptor. Don’t try to time your way into a hospital inpatient code the same way you would an office visit — the rules differ by category, which the next section covers.

Hospital Inpatient and Observation Care: 99221-99239

Before 2023, hospital inpatient and observation care had entirely separate code sets — observation used 99217-99220 and 99224-99226, inpatient used 99221-99233 and 99238-99239. As of January 1, 2023, those observation-specific codes were deleted, and inpatient and observation services now share one merged code set:

The patient’s facility status (inpatient vs. outpatient/observation) still matters for the place of service code reported on the claim — but it no longer determines which CPT code is selected. Level selection for all of these follows the same MDM-or-time logic as office visits.

📌 CPC Exam Tip: If a practice question or older study material references codes 99217-99220 or 99224-99226, that’s outdated — those codes were deleted in 2023. The CPC exam is built on current-year guidelines, so seeing one of those numbers as an answer choice is a strong signal it’s a distractor.

Emergency Department, Critical Care, and Other E/M Categories

Several E/M categories outside the office and hospital setting are frequently tested:

Critical care has a documentation quirk worth knowing: time spent must be continuous attention to that one patient, and certain bundled services (like ventilator management and interpretation of cardiac output measurements) are included in 99291/99292 and can’t be billed separately when performed for the same patient during that critical period.

Modifier 25: Billing an E/M Visit With a Same-Day Procedure

A common exam scenario: a patient comes in for a problem, and during that same visit the physician also performs a minor procedure — say, a skin tag removal during what started as a blood pressure check. Because most minor procedures already include some pre- and post-procedure E/M work in their own valuation, billing a separate E/M code on top requires proof that the E/M service was significant and separately identifiable from the procedure itself. That’s what modifier 25 communicates — it tells the payer the E/M visit stood on its own, not that the visit was simply more complex than usual.

This connects directly to the global surgical package: an E/M visit performed during the global period of an unrelated prior procedure may also need modifier 24 (unrelated E/M during a postoperative period) rather than 25 — a distinction the exam likes to test by swapping one modifier for the other in similar-sounding scenarios.

The G2211 Add-On Code: Visit Complexity

G2211 is a HCPCS Level II add-on code — not a CPT code — that captures the added complexity of an ongoing, longitudinal patient relationship, separate from whatever is reflected in the base E/M code itself. It’s reported in addition to an eligible base E/M code, never alone.

As of 2026, G2211 can be billed with:

• Office/outpatient E/M codes 99202-99205 and 99211-99215
• Home or residence visit codes 99341-99350 (newly eligible starting January 1, 2026)

G2211 cannot be billed with emergency department, nursing facility, or hospital inpatient/observation E/M codes. Because it’s a HCPCS Level II code rather than a CPT code, it’s billed and tracked separately from the E/M visit level itself, but it still rides along with that same claim line.

📌 CPC Exam Tip: G2211 doesn’t change which E/M level you select — it’s an add-on reported alongside the level already determined by MDM or time. Don’t let a question about G2211 distract you into second-guessing the base code.

Putting It Together: A Coding Scenario

A 45-year-old established patient is seen for a 25-minute visit addressing two complaints: worsening seasonal allergies and a request to discuss starting a statin after a recent elevated cholesterol panel reviewed before the visit. The physician orders no new tests, discusses the risks and benefits of statin therapy, and prescribes one.

Clinical example: Walking through MDM: problems addressed are two — one self-limited (allergies) and one chronic with a new treatment decision (cholesterol management), which together land at moderate complexity. Data reviewed includes the outside lab panel, which counts toward at least limited, possibly moderate, data. Risk includes prescription drug management, which the 2021 table sets at moderate risk regardless of how minor the specific drug seems. Two of the three columns — problems and risk — clear the moderate threshold, so this visit codes to 99214, not the lower 99213 a coder might default to if they weighted the visit’s short length instead of its actual decision-making complexity.

That last point is the core skill E/M questions are testing: visit length and visit complexity are not the same thing, and only time-based coding cares about the former.

Frequently Asked Questions