What Is Medical Decision Making (MDM) in E/M Coding? Complete 2026 Guide
Medical Decision Making (MDM) is the clinical reasoning framework used to determine the complexity of an Evaluation and Management (E/M) encounter under the AMA 2021 guidelines. MDM evaluates three elements — the number and complexity of problems addressed, the amount and complexity of data reviewed or ordered, and the risk of complications, morbidity, or mortality — to assign one of four complexity levels: straightforward, low, moderate, or high. The MDM level directly determines the E/M CPT code billed for outpatient office visits (99202–99215).
Since the AMA and CMS adopted the 2021 E/M documentation guidelines, MDM has become the primary method for selecting E/M codes. The prior system based on history and physical exam components was eliminated for office and outpatient visits. Under the current framework, physicians use the 2-of-3 rule: two out of three MDM elements must meet or exceed a given complexity level. Alternatively, physicians may bill based on total encounter time if it supports a higher code. Studies show that 23–31% of outpatient E/M encounters are undercoded, costing U.S. practices an estimated $36 billion annually in lost revenue — much of which stems from MDM scoring errors.
The 3 Elements of Medical Decision Making
Every E/M encounter is scored on three independent MDM elements. Each element is evaluated separately, and the 2-of-3 rule is applied to determine the final MDM level.
Element 1: Number and Complexity of Problems Addressed
This element measures the clinical problems the physician actively managed during the encounter — not just the diagnoses listed. Problems must be “addressed” in the note, meaning the physician evaluated, assessed, or treated them.
- Minimal: 1 self-limited or minor problem (e.g., cold, insect bite, uncomplicated rash)
- Low: 2 or more self-limited problems, OR 1 stable chronic illness (e.g., controlled hypertension, stable diabetes)
- Moderate: 1 or more chronic illnesses with mild exacerbation, progression, or side effects of treatment, OR 1 undiagnosed new problem with uncertain prognosis (e.g., unexplained chest pain, new-onset headaches)
- High: 1 or more chronic illnesses with severe exacerbation, progression, or side effects, OR 1 acute or chronic illness or injury that poses a threat to life or bodily function (e.g., acute MI, pulmonary embolism, suicidal ideation)
Element 2: Amount and Complexity of Data Reviewed or Ordered
This element measures the clinical data the physician reviewed, ordered, or analyzed. It uses three scoring categories defined by the AMA:
- Category 1 — Tests and documents: Reviewing or ordering labs, imaging, records from external sources, or obtaining history from an independent historian (not the patient). Each unique source contributes points.
- Category 2 — Independent interpretation: The physician personally interprets a test they did not order (e.g., reading an EKG, reviewing imaging). This is separate from simply ordering the test.
- Category 3 — Discussion with external physician: Documented discussion with an external physician or qualified health professional about the case management or test results.
The data levels are:
- Minimal or none: No data reviewed or minimal data
- Limited: Category 1 sources only (e.g., reviewed prior labs)
- Moderate: 2 or more Category 1 sources, OR any Category 2 or 3 activity
- Extensive: 2 or more Category 1 sources AND any Category 2 or 3 activity
Element 3: Risk of Complications and/or Morbidity or Mortality
This element is based on the CMS Table of Risk, which categorizes the highest-risk management decision made during the encounter. Only one risk factor needs to qualify — it is not cumulative. The highest applicable risk level sets the element score.
CMS Table of Risk Summary
| Risk Level | Examples of Management Options |
|---|---|
| Minimal | Rest, bandages, superficial dressings, OTC drugs, elastic bandages |
| Low | Prescription drug management (new or continued), minor surgery with no identified risk factors, physical therapy, occupational therapy |
| Moderate | Prescription drug management requiring intensive monitoring (e.g., warfarin, chemotherapy agents), decision regarding minor surgery with identified risk factors, elective major surgery, diagnosis or treatment significantly limited by social determinants of health, IV fluids without additives |
| High | Drug therapy requiring intensive monitoring for toxicity (e.g., immunosuppressants), decision regarding emergency major surgery, decision regarding hospitalization or ICU care, DNR or de-escalation of care decisions with significant patient/family discussion |
The 4 MDM Complexity Levels
Once each element is scored, the 2-of-3 rule determines the overall MDM level. Here is the complete MDM table used for AMA 2021 E/M coding:
| MDM Level | Problems | Data | Risk |
|---|---|---|---|
| Straightforward | 1 self-limited/minor problem | Minimal or none | Minimal risk |
| Low | 2+ self-limited OR 1 stable chronic | Limited (Category 1 only) | Low risk (Rx drugs, minor surgery) |
| Moderate | 1 chronic with exacerbation OR 1 undiagnosed new problem | Moderate (2+ Cat 1, or any Cat 2/3) | Moderate risk (intensive Rx monitoring, elective surgery) |
| High | Severe exacerbation OR threat to life/function | Extensive (2+ Cat 1 AND Cat 2/3) | High risk (hospitalization, IV drugs, DNR) |
MDM Level to E/M Code Mapping
Each MDM level maps directly to specific E/M CPT codes for office and outpatient visits. New patient codes reimburse 30–50% higher than established patient codes at the same MDM level.
| MDM Level | New Patient Code | Established Patient Code | 2024 Medicare Avg Reimbursement |
|---|---|---|---|
| Straightforward | 99202 | 99212 | $67–$76 |
| Low | 99203 | 99213 | $109–$111 |
| Moderate | 99204 | 99214 | $167–$170 |
| High | 99205 | 99215 | $211–$224 |
The revenue difference between adjacent codes is significant. Billing 99214 instead of 99213 adds approximately $55–$65 per encounter. For a practice seeing 20 patients daily, correcting undercoding on just 3 encounters per day recovers $40,000–$50,000 annually. Read more about this gap in our guide on 99213 vs 99214: When to bill the higher code.
How to Apply the 2-of-3 Rule: A Worked Example
Consider an established patient visit for uncontrolled diabetes (A1c 8.9%) with new peripheral neuropathy symptoms. The physician reviews recent lab results and a specialist consultation note, adjusts metformin dosage, and orders an EMG.
- Problems: 1 chronic condition with exacerbation (uncontrolled DM) + 1 undiagnosed new problem (neuropathy symptoms) = Moderate
- Data: Reviewed labs (Category 1) + reviewed external specialist note (Category 1) + ordered EMG (Category 1) = 3 Category 1 sources = Moderate
- Risk: Prescription drug management (metformin dose change) = Low
Apply the 2-of-3 rule: Moderate, Moderate, Low → drop the lowest (Low) → MDM level = Moderate. This maps to 99214 for an established patient. If the physician also documented 35 minutes of total encounter time, the time-based code would also be 99214 (30–39 min range).
MDM vs Time-Based Coding: When to Use Each
Under the AMA 2021 guidelines, E/M codes can be selected based on either MDM or total time — whichever yields the higher code. Time-based coding is particularly advantageous for care coordination-heavy visits where the physician spends significant time on record review, care planning, and phone calls that don’t generate high MDM complexity.
For example, a 40-minute encounter managing stable chronic conditions (MDM = Low = 99213) would qualify for 99215 on time alone for an established patient. Tools like CodeItRight’s AI analyzer automatically compare both methods and recommend whichever code yields higher reimbursement.
See the complete time thresholds in our E/M Code Levels Chart 2026 or use the manual E/M calculator to practice scoring.
5 Common MDM Mistakes That Cost Physicians Revenue
- Defaulting to 99213 without scoring MDM. Many physicians habitually bill 99213 for routine visits. National data shows the average internist bills 99214 for 45–52% of established visits. If your 99213 rate exceeds 50%, you are likely undercoding.
- Not counting prescription drug management as moderate risk. Any encounter involving prescribing, continuing, or adjusting a prescription medication qualifies as at least Low risk. This is the single most under-scored element.
- Missing independent interpretation credit. If you personally read an EKG, X-ray, or lab result (rather than just reviewing someone else’s interpretation), document it explicitly: “I independently interpreted the EKG.” This upgrades data from Limited to Moderate.
- Forgetting external physician discussion credit. When you call a specialist, document: “Discussed management with Dr. Smith, cardiology.” This provides Category 3 data credit.
- Ignoring time-based coding. If you spent 35+ minutes, document total time. Many physicians qualify for 99214 or 99215 on time alone but never capture it. See the E/M Cheat Sheet for quick time thresholds.
Frequently Asked Questions
What is Medical Decision Making (MDM) in E/M coding?
Medical Decision Making (MDM) is the clinical reasoning framework used under AMA 2021 guidelines to determine the complexity of an outpatient Evaluation and Management (E/M) encounter. MDM evaluates three elements — number and complexity of problems addressed, amount and complexity of data reviewed or ordered, and risk of complications — and uses the 2-of-3 rule to assign one of four complexity levels: straightforward, low, moderate, or high. The MDM level directly maps to the E/M CPT code billed (99202-99215).
How does the MDM 2-of-3 rule work?
The 2-of-3 rule means that two out of three MDM elements must meet or exceed a given complexity level for the encounter to qualify at that level. The three elements are: (1) problems addressed, (2) data reviewed, and (3) risk of management. You score each element independently, then drop the lowest. The middle value determines the MDM level. For example, if problems = Moderate, data = High, and risk = Low, you drop the Low — the MDM level is Moderate.
What are the 4 levels of Medical Decision Making?
The four MDM levels are: (1) Straightforward — 1 self-limited or minor problem, minimal data, minimal risk; maps to 99202/99212. (2) Low — 2+ self-limited problems or 1 stable chronic condition, limited data, low risk (prescription drug management); maps to 99203/99213. (3) Moderate — 1 undiagnosed new problem or chronic condition with exacerbation, moderate data, moderate risk; maps to 99204/99214. (4) High — acute illness with threat to life or bodily function, extensive data, high risk (hospitalization, IV drugs, DNR decisions); maps to 99205/99215.
What is the CMS Table of Risk?
The CMS Table of Risk is a reference table that categorizes the risk element of MDM into four levels: Minimal (rest, OTC drugs, bandages), Low (prescription drug management, minor surgery with no identified risk factors), Moderate (prescription drug management requiring intensive monitoring, elective major surgery, IV fluids without additives), and High (hospitalization, drugs requiring intensive monitoring, emergency surgery, DNR/de-escalation of care decisions). The highest-risk management option documented in the encounter sets the risk level.
Can I use time-based coding instead of MDM?
Yes. Under AMA 2021 guidelines, physicians can bill E/M codes based on either MDM complexity OR total time on the date of the encounter — whichever yields the higher code. Total time includes face-to-face time, care coordination, record review, documentation, and order placement. For established patients, time thresholds are: 99212 (10-19 min), 99213 (20-29 min), 99214 (30-39 min), 99215 (40-54 min). Always document total time to preserve the time-based billing option.
What is the difference between MDM for new patients vs established patients?
The MDM complexity levels are identical for new and established patients — the same 2-of-3 scoring applies. The difference is the CPT code assigned: new patients use 99202-99205 and established patients use 99212-99215. New patient codes reimburse 30-50% higher than established patient codes at the same MDM level because new patient encounters typically require more history gathering and documentation. Note that 99201/99211 were eliminated under the 2021 guidelines (99211 remains as a nurse visit code with no MDM requirement).
How do I score the "data" element of MDM?
The data element is scored using three categories. Category 1: Ordering or reviewing tests, documents, or independent historian — each unique source earns points (2 points for each category of test/document, 1 point for assessment of independent historian). Category 2: Independent interpretation of a test you did not order — earns additional credit if you personally interpret results (e.g., reading an EKG). Category 3: Discussion of management or test interpretation with external physician/qualified health professional — earns credit when you document consulting with another doctor. Minimal = no data or review of minimal data. Limited = Category 1 only. Moderate = 2+ Category 1 sources OR any Category 2 or 3. Extensive = 2+ Category 1 sources AND Category 2 or 3.
What are common MDM scoring mistakes that lead to undercoding?
The most common MDM scoring mistakes are: (1) Defaulting to 99213 without scoring MDM — studies show 23-31% of encounters are undercoded. (2) Not counting prescription drug management as moderate risk — any new or continued Rx qualifies. (3) Missing Category 2/3 data credit — documenting "I independently interpreted the EKG" upgrades data from Limited to Moderate. (4) Ignoring time-based coding — physicians spending 35+ minutes often qualify for a higher code on time alone. (5) Counting stable chronic conditions as minimal — 2+ stable chronic conditions = Low complexity, and 1 chronic condition with exacerbation = Moderate.
Automate MDM Scoring With AI
Manually scoring MDM elements takes 8–12 minutes per note. AI-powered tools like CodeItRight.ai extract all three MDM elements from your clinical note in under 30 seconds, apply the 2-of-3 rule deterministically, compare against time-based codes, and generate audit-ready documentation. The result is dual codes (MDM vs time), gap analysis showing where documentation could support a higher level, and a SOAP-formatted summary ready for your EHR.
Learn more about how AI handles MDM scoring in our guide on What Is AI Medical Coding?, or explore the complete MDM Levels Explained deep dive on our blog.