99213 CPT Code Description, Guidelines, and Reimbursement

In the complex landscape of medical billing, CPT code 99213 stands as one of the most frequently used—and scrutinized—codes in the outpatient setting. It’s a workhorse for primary care, internal medicine, and specialists alike, representing a typical follow-up visit for an established patient.

But what makes a visit a "99213"? Since the sweeping Evaluation and Management (E/M) guideline changes in 2021, the rules for reporting 99213 are no longer based on the old, cumbersome "history and exam" bullet points. Today, coding is simpler but requires a completely different mindset.

Misunderstanding these new rules is a direct path to claim denials, downcoding, and audit-related takebacks. This article breaks down the modern guidelines for CPT code 99213, how to document for it, and what to expect for reimbursement.

The 2021 E/M Revolution: A New Foundation for 99213

Before 2021, billers and providers were forced to count elements in the History of Present Illness (HPI), Review of Systems (ROS), and physical exam. This led to "note bloat" and documentation that served auditors, not patient care.

The 2021 E/M guidelines (updated in 2023) fundamentally changed this. Now, code selection for office and outpatient E/M codes (99202-99215) is based on only one of two criteria:

1. Total Time spent by the provider on the date of the encounter.

2. The level of Medical Decision Making (MDM).

This means the provider, coder, and biller must ask a new question: "Did this visit meet the criteria for Low-Level Medical Decision Making, or did the provider spend 20-29 minutes on the patient's care today?"

What is CPT Code 99213? The Official Definition

First, let's establish the basics. CPT code 99213 is officially defined as an:

Office or other outpatient visit for the evaluation and management of an established patient, which requires a medically appropriate history and/or examination and a low level of medical decision making. When using time for code selection, 20-29 minutes of total time is spent on the date of the encounter.

The most critical phrase here is "established patient." This code cannot be used for new patients (those who have not been seen by the provider or another provider of the same specialty in the same group within three years). Billing 99213 for a new patient is a guaranteed denial.

Pathway 1: Billing 99213 Based on Medical Decision Making (MDM)

This is the most common method for billing 99213. To qualify, the visit must meet the criteria for a "Low" level of MDM.

MDM is composed of three elements. To qualify for a "Low" level, the provider's documentation must meet or exceed the requirements for two out of the three elements.

1. Number and Complexity of Problems Addressed:

   • What it means for 99213 (Low): The documentation should show:

     • Two or more self-limited or minor problems (e.g., a follow-up for a cold and a simple rash).

     • One stable chronic illness (e.g., a routine 3-month check-in for stable hypertension).

     • One acute, uncomplicated illness or injury (e.g., a patient with a simple UTI or an ankle sprain).

2. Amount and/or Complexity of Data to be Reviewed and Analyzed:

   • What it means for 99213 (Limited): The visit must meet at least one of the following:

     • Review of a single test result (e.g., "Reviewed patient's recent A1c").

     • Review of prior external records from a single source.

     • Ordering of one unique test (e.g., "Ordered a CBC").

   • Note: Simply reviewing a patient's self-reported blood pressure log does not count. The data must be analyzed, or a new test must be ordered.

3. Risk of Complications and/or Morbidity or Mortality of Patient Management:

   • What it means for 99213 (Low): This category includes management decisions such as:

     • Rest, gargles, or elastic bandages.

     • Management of over-the-counter (OTC) drugs.

     • Not prescription drug management. According to AAPC guidelines on MDM, the decision to start or manage prescription medication typically raises the risk to "Moderate," which would support a 99214.

Real-World Example (MDM): A 65-year-old established patient comes in for a 3-month follow-up for stable, well-controlled hypertension. The provider reviews the patient's home blood pressure log, performs a medically appropriate exam, and notes the condition is stable. No new tests are ordered, and no medication changes are made.

• Problems: 1 stable chronic illness (Low).

• Data: None (review of a home log doesn't count as "analyzing data").

• Risk: Low (no prescription changes).

Since this visit meets 2 of 3 elements (Problems and Risk) at the "Low" level, it correctly qualifies as a 99213.

Pathway 2: Billing 99213 Based on Total Time

This is the simpler, more objective pathway. If the visit doesn't clearly meet the MDM criteria, but the provider spent significant time on the patient's care, time-based billing is the answer.

For CPT code 99213, the requirement is 20-29 minutes of total time on the date of the encounter.

What is "total time"? This is a critical definition. It is not just face-to-face time. It includes all provider work performed on the day of the visit, such as:

• Reviewing the patient's chart, lab results, or imaging before the visit.

• Performing the face-to-face (or telehealth) exam and visit.

• Documenting the visit in the EMR.

• Ordering medications, labs, or imaging.

• Coordinating care with other providers (e.g., sending a note to a specialist).

Real-World Example (Time): A patient presents with a simple URI. The provider spends 10 minutes in the room with them. However, before the visit, the provider spent 5 minutes reviewing their chart and recent urgent care visit notes. After the visit, the provider spent 7 minutes documenting the note and sending a prescription for OTC cough medicine.

• Total Time: 5 min (review) + 10 min (visit) + 7 min (documentation) = 22 minutes.

• Because the total time falls within the 20-29 minute window, this visit qualifies as a 99213, even if the MDM was only "Straightforward."

Documentation: How to Create an Audit-Proof 99213 Note

Under the new guidelines, your documentation must defend your code selection. "If it wasn't documented, it didn't happen."

• If billing on MDM: Your "Assessment and Plan" is now the most important part of the note. It must clearly state the status of the problems (e.g., "Hypertension, stable") and the data reviewed or risk involved (e.g., "Reviewed BMP, labs are stable. Continue current therapy."). A vague note won't pass an audit.

• If billing on Time: Your note must include a time attestation statement. Without this, you cannot support the code.

  • Example Attestation: "I spent a total of 25 minutes on this patient's care on [Date of Service]. This time included reviewing the patient's chart, performing the visit, documenting the encounter, and ordering a new lab test."

Reimbursement and RVUs for 99213

How much does a 99213 pay? Reimbursement is based on a formula: Total Relative Value Units (RVUs) multiplied by the annual Medicare Conversion Factor (CF).

• RVUs: The 2024 national average total (non-facility) RVU for 99213 is approximately 2.68. This value combines provider work, practice expense, and malpractice insurance cost.

• Conversion Factor: The 2024 Medicare Conversion Factor is $32.7442 (a decrease from 2023).

Example Calculation: 2.68 (RVUs) x $32.7442 (CF) = ~$87.75

This is the national Medicare average. The exact reimbursement will vary based on your geographic location (GPCI) and your specific contracts with commercial payers. You can always check the rates for your specific locality using the CMS Physician Fee Schedule (PFS) Look-Up Tool.

Common Mistakes: 99213 vs. 99214 and Other Denials

1. 99213 (Low MDM) vs. 99214 (Moderate MDM): This is the most common E/M coding error. Upcoding to 99214 is a major audit risk. The key difference is the complexity.

• 99213 (Low): 1 stable chronic illness OR 1 acute, uncomplicated illness.

  • Example: Stable hypertension, no med changes.

• 99214 (Moderate): 1 chronic illness with exacerbation OR 1 undiagnosed new problem with an uncertain prognosis OR 2+ stable chronic illnesses.

  • Example: Hypertension with high readings requiring a new prescription (this is "prescription drug management," which qualifies as Moderate Risk).

2. Appending Modifier 25 Incorrectly: This is a constant target for payers. Modifier 25 is used on an E/M code (like 99213) when a significant, separately identifiable E/M service is performed on the same day as a minor procedure.

• Correct Use: A patient comes in for a 99213 follow-up for their diabetes (a significant, separate service), and during the visit, they also ask the provider to remove a skin tag (a minor procedure). The provider can bill for both the procedure and the 99213-25.

• Incorrect Use: A patient comes in only for a scheduled joint injection. The brief evaluation to confirm the injection site is not a separate E/M service. Appending a -25 here is improper. The documentation, as noted by the AMA's guidelines for Modifier 25, must show a distinct and separate history, exam, and/or MDM.

3. Billing Time without an Attestation: As mentioned, if you bill based on the 20-29 minute window, the total time must be documented in the note. No attestation means no support for the code.

By mastering the dual pathways of MDM and time, ensuring documentation is precise, and understanding the common pitfalls, CPT code 99213 can be a reliable and compliant source of revenue for your practice.