Your 2025 Guide to E/M Coding

When it comes to Evaluation & Management (E/M) coding, even experienced medical coders can get tripped up over when to use time-based codes and when to use Medical Decision Making (MDM) codes. 

The distinction may seem fuzzy, but it’s important. With medical practices facing rising costs and falling reimbursements, regularly using the wrong code could have a serious impact on cash flow. 

Plus, a renewed focus at the Centers for Medicare & Medicaid Services (CMS) on coding accuracy makes errors a compliance risk that could lead to audits and penalties. 

In this guide, we’ll cover 2025 updates to CMS guidelines for E/M coding and offer clarity on when to use time-based and when to use MDM. 

What Is E/M Coding? 

E/M codes are Current Procedural Terminology (CPT) codes that categorize services performed in the evaluation and management of a patient’s health (as opposed to services to treat an illness or injury). 

Coders can choose whether to code an E/M service based on how long it took or how complex it was. 

Time-Based Coding 

Time-based coding covers the total time a qualified healthcare provider spends on the patient visit. It includes face-to-face time with the patient as well as time spent on tasks like reviewing records, charting, and consulting with other clinicians. 

Time-based coding is especially useful to specialty practices like ophthalmology, dermatology, and plastic surgery, where clinicians can spend a significant amount of time counseling patients, explaining their options, and coordinating care. 

For example, a dermatologist may spend a lot of time counseling a patient on the pros and cons of a biologic treatment, even if the condition being treated is relatively low risk. In that scenario, it makes more sense to bill for the time than for the complexity. 

Coders need to be careful — time-based coding can only be used to bill for the services of specific types of clinicians. It does not cover time spent by support staff on the same patient encounter. 

Medical Decision Making (MDM) 

The other option for E/M coding is MDM coding, which is based not on time, but on the complexity of the encounter. There are five possible levels of complexity, from straightforward to highly complex. 

MDM is measured across three elements: 

• The number and complexity of problems addressed,
• The amount or complexity of data to be analyzed, and
• The risk of morbidity or mortality.

For instance, if a cosmetic surgery patient returns for a post-op visit with signs of infection, the plastic surgeon may take only a few minutes to examine the incision, order labs, and prescribe antibiotics. But the risk of morbidity, the complexity of care, and the decision of whether to return to the OR justify coding based on MDM. 

Why It Matters 

The length of a visit doesn’t always reflect its complexity, and vice versa. Coders are tasked with choosing the E/M code that most accurately reflects what happened to get fair reimbursement for the practice. 

Here are 10 common outpatient E/M codes and how they would be categorized by time or complexity: 

2025 E/M Coding Updates 

Changes to E/M codes in the 2025 CPT update include expanding use of G2211 and updating the Telehealth Services list. 

Expansion of G2211 

In 2025, CMS changed the rule regulating when a practice can use complexity code G2211. It can now be used on the same day as a visit for preventive services, like wellness visits and vaccine administration. 

Telehealth Services Update 

Many statutory limits on Medicare payments for telehealth services were temporarily suspended in 2020 in response to the COVID-19 pandemic. 

The five-year suspension ran out this year, and most telehealth limitations were reinstated for Medicare patients. 

CMS did, however, add some services to the Medicare Telehealth Services list, including PrEP counseling and safety planning interventions. 

CMS Rejected Some CPT Updates 

CPT codes are updated annually by the American Medical Association. In 2025, the AMA created new E/M codes for some telehealth visits. 

CMS, which administers Medicare, rejected all but one of these new codes. Coders billing Medicare will now use CPT 98016 to replace G2012. Otherwise, telehealth visits billed to Medicare must be coded using in-person E/M codes with Modifier 93. 

This is bound to make coding telehealth visits more complex for coders. Medicare’s decision to reject new codes doesn’t prevent private insurers from adopting them. 

So coders must evaluate not only which kind of code is appropriate, but which payer is being billed and which CPT codes they accept. 

Practice administrators can take some of the pressure off their coding staff by using a practice management platform with smart tools. Tools can be set up to different coding options based on payer and to alert coders when something doesn’t look right, reducing the risk of errors. 

Common E/M Coding Mistakes 

E/M coding is anything but straightforward, and can cause even experienced coders to stumble. Mistakes can lead to denials, noncompliance, and underpayment. 

Common errors include counting the wrong activities toward time-based billing, double-counting data in MDM billing, misapplying a code, not meeting time or complexity thresholds, lack of documentation, and confusing CMS and payer codes. 

Counting the Wrong Activities 

In time-based coding, only the time of a qualified healthcare provider counts, and only if it is spent on the same day as the patient visit. 

For example: 

• A medical assistant gathering documentation before a patient visit cannot be included in time-based billing, but the clinician’s time reviewing the documents can.
• An ophthalmologist reviewing a patient’s images on Monday cannot apply that time to the patient encounter on Tuesday, even if the image review was to prepare for the visit.

These are the only providers whose time can be counted toward time-based billing: 

• Certified nurse specialist
• Clinical social worker
• Certified registered nurse anesthetist
• Doctor of osteopathy
• Medical doctor
• Nurse practitioner
• Physician assistant
• Physical therapist

And these are the only activities that can be counted toward their time (all activities must take place the same day as the patient visit): 

• Preparing to see the patient
• Obtaining or reviewing separately obtained history
• Performing an appropriate and medically necessary exam or evaluation
• Ordering medications, tests, or procedures
• Counseling and educating the patient or their caregiver
• Referring and consulting with other health care providers
• Charting
• Interpreting results and reporting them to the patient or caregiver
• Care coordination

Double-Counting Data 

In time-based billing, a coder can count the time a clinician spends ordering lab work and time they spend reviewing the result. 

In MDM billing, “data reviewed and analyzed” is one element, not two data points. 

Misapplying Codes 

One of the most common E/M errors is using MDM when time-based billing would provide a higher reimbursement. 

For example, if an orthopedic surgeon spends 40 minutes counseling a patient about joint replacement, it could be coded as MDM 99213. But time-based code 99215 could also apply — and reimburse as much as 86% more. 

To choose the right code, use a customizable, specialty-specific EHR that can help clinicians chart both the complexity and time spent on the encounter. 

Nextech’s specialty-specific platform pulls coding information directly from the patient chart, so coders can choose the code with the highest reimbursement. 

Not Meeting Time or Complexity Thresholds 

When using time-based billing, coders cannot round up. Each level of complexity has minimum time thresholds. If a clinician is as little as a minute or two away from the higher threshold, the service must be billed at the lower level. 

Similarly, in MDM coding, coders must not overstate the problem’s complexity. For example, a stable chronic illness like diabetes is categorized as low complexity, not moderate. 

Be precise about whether a condition is stable, worsening, or has complications when categorizing its complexity. 

Lack of Documentation 

It’s vital clinicians accurately document their activities, rather than leaving coders to guess. Charting a 40-minute visit as “40 minutes counseling patient” is vague and likely to raise red flags for auditors. 

A better chart entry would read, “40 minutes total time spent reviewing MRI, counseling patient on surgical vs. nonsurgical treatment, and documenting findings.” 

This applies to MDM coding, too. Coders can’t use comorbidities to justify a higher complexity unless the chart notes how those comorbidities factor into medical decisions. 

Documentation errors often happen when clinicians are completing a backlog of charts at the end of the day and relying on their memory instead of technology. 

A visit that felt like 45 minutes may have only had 25 minutes of qualifying time. A decision that seems obvious to the provider may not be so obvious to an auditor reviewing the chart. 

Nextech’s streamlined, intuitive interface and smart tools enable providers to finish charting in minutes. In some cases, providers report being finished with their patient notes while the patient is still checking out at the front desk — no backlog to catch up on and no depending on memory to get the details right. 

Confusion Between CMS and Commercial Payers 

As noted earlier, not every payer adopts the same updates to CPT codes at the same time. Sending a bill to Medicare that lists a code the government doesn’t use will usually mean a denial, rework, and a delay in reimbursement. 

Avoid this pitfall by creating payer-specific coding rules in your EHR so the system recognizes whether the codes you use are correct. 

Practical Tools for E/M Coding 

Whether you’re coding by time or complexity, a specialty-specific EHR is a wise investment. 

Every specialty has some common scenarios where one methodology is preferred over the other. A specialty-specific platform can be set up to recognize and alert coders to conditions that would make time-based or MDM more suitable. 

Tools for Time-Based Coding 

EHR-Integrated Time Tracking. Relying on memory and notes runs the risk of misreporting total time. Instead, use a time tracker integrated into your EHR to automatically capture the time you spend in a patient’s chart. 

Log time spent on counseling and coordination of care directly into the visit note immediately after the patient encounter. When capturing billable time is part of your normal workflow, it lowers the risk of manual errors. 

Document Templates. Auditors look not only at total time, but at what happened during that time. You can save time on manual data entry by creating customized templates in your EHR that auto-populate with the most common activities and how long they typically take. 

Tools for MDM Coding 

EHR-Integrated MDM Prompts. It’s tough to make an accurate judgment of the three elements of complexity based only on your memory hours or days after an encounter. 

Use Nextech’s sleek, one-page EHR interface to guide you through recording the number and severity of problems, the data gathered or reviewed, and the risk factors the patient faces in real time. 

Document Templates. Create templates that prompt providers to analyze and record each element of MDM. Use smart fields to auto-populate specialty-specific data points like imaging reports or biopsy orders. 

E/M Coding Checklists 

Time-Based Coding Checklist 

MDM Coding Checklist 

Excel at E/M Coding to Safeguard Practice Revenue 

E/M coding can be tricky to master, but when it’s used correctly, it helps your practice get reimbursed at the best rate, while protecting you from noncompliance. 

Review code updates annually to avoid underpayment and compliance issues. And implement a specialty-specific EHR and practice management platform that simplifies charting and reduces errors in coding. 

Request a demo today.