Current Procedural Terminology (CPT) codes are the standardized language used by the healthcare system to report services provided by clinicians. Maintained by the American Medical Association (AMA), these codes form the basis for medical billing and tracking the frequency of care delivered. CPT code 99213 represents a specific level of service for an office or outpatient visit, making it one of the most frequently used codes in primary care. This code signifies a mid-range Evaluation and Management (E/M) service on the complexity scale for common follow-up care. Understanding the requirements for 99213 ensures providers are appropriately reimbursed for the time and cognitive effort involved in a patient encounter.
Defining the Level 3 Established Patient Visit
CPT code 99213 is designated for an office or outpatient visit involving an established patient. An established patient is defined as someone who has received professional services from the physician or a qualified health care professional within the same group practice within the past three years. This designation is important because new patient visits require a more thorough initial history and examination and use a different series of codes.
This code represents a Level 3 visit, indicating a low level of complexity in the medical decision-making process (MDM). The visit involves the evaluation and management of conditions that are not severe or rapidly worsening. A common use is a follow-up appointment for a patient with a stable chronic illness, such as well-controlled hypertension or type 2 diabetes.
It may also be used for an acute, uncomplicated illness or injury, such as a minor rash, a simple urinary tract infection, or an upper respiratory infection. Care focuses on monitoring the stable condition, adjusting medications slightly, or addressing a new, straightforward issue. While the provider must perform a medically appropriate history and examination, billing is primarily driven by either the total time spent or the complexity of the medical decisions made.
Documentation Requirements for Billing
Providers can justify billing for CPT code 99213 in two ways: based on the total time spent on the date of the encounter or based on the complexity of the Medical Decision Making (MDM). The time-based approach requires the clinician to document the total time spent on the date of the service. For this Level 3 established patient visit, the AMA defines the required time interval as 20 to 29 minutes.
This total time includes all activities performed by the provider on the day of the visit. These activities include preparing to see the patient, reviewing documentation, performing the examination, counseling the patient, and documenting the service. If the time spent falls within the 20 to 29 minute range, the visit qualifies for the 99213 code, regardless of the MDM complexity.
Alternatively, the visit can be coded based on the complexity of the MDM, which for CPT 99213 must be at a “Low” level. MDM is assessed by considering three elements: the number and complexity of problems addressed, the amount and complexity of data reviewed, and the risk associated with the patient management plan. To meet the Low MDM requirement, documentation must support at least two of these three elements at the low level.
The Low MDM threshold is met by addressing one stable chronic illness or two self-limited or minor problems. The data element is satisfied by reviewing a limited number of test results, such as a single lab test or a past medical record. The risk element is considered low when the management plan involves over-the-counter medications, minor surgery without risk factors, or a decision to stop or start a non-high-risk medication.
How This Visit Compares to Other Service Levels
To understand where CPT 99213 sits within the established patient E/M codes, it is helpful to compare it to the adjacent levels, 99212 and 99214. The lowest level, CPT 99212, represents a minimal service encounter, requiring a straightforward MDM or 10 to 19 minutes of total time. This code is used for very brief visits, such as a quick check-in for a simple prescription refill or a minor, self-limited problem.
In contrast, CPT 99214 signifies a moderate complexity visit, requiring a moderate MDM or 30 to 39 minutes of total time. This level is appropriate for patients with multiple poorly controlled chronic conditions or a single severe acute illness. Documentation for 99214 shows significantly more work, such as interpreting multiple imaging studies or lab panels, consulting with other providers, or managing a high-risk medication change.
The Level 3 code, 99213, occupies a middle ground. It manages issues that are more involved than a simple check-in (99212) but less complex than those requiring extensive data review or high-risk management (99214). It is often the default code for routine follow-up care that necessitates a thoughtful assessment of a stable condition. The difference in time between 99213 and 99214 reflects the greater cognitive effort required for more complicated clinical scenarios.