Current Procedural Terminology (CPT) codes establish a standardized language used by healthcare providers and payers to report medical services. These numeric codes ensure uniform communication about procedures, tests, and patient encounters. CPT code 99233 belongs to a category known as Evaluation and Management (E/M) services, which describe the work involved in assessing and managing a patient’s health condition. This code is utilized within the hospital setting, applying to services delivered to patients who are admitted for inpatient or observation care. The E/M codes are structured to reflect the complexity and time required for the clinical encounter, making CPT 99233 an indicator of a high-intensity service.
Definition of Subsequent Hospital Care
CPT code 99233 is the highest level code within the range designated for Subsequent Hospital Inpatient or Observation Care (99231-99233). This code is reported for a daily visit to a patient already admitted to a facility, meaning it is used after the initial hospital admission but before the patient is formally discharged. The service encompasses a complete re-evaluation of the patient’s status, including a review of their medical chart, diagnostic results, and response to ongoing treatment. It is distinct from the codes used for the initial hospital admission (99221-99223) or the final hospital discharge service (99238/99239). The description of the code was updated to apply equally to both the hospital inpatient setting and the observation care setting, meaning the same criteria for complexity and time are used regardless of the patient’s status.
Documentation Requirements for High Complexity
A healthcare provider selects CPT 99233 over lower-level codes (99231 or 99232) by demonstrating that the encounter met the requirements for a high level of complexity. This qualification can be achieved through one of two methods: the extent of Medical Decision Making (MDM) or the total time spent on the patient’s care on the date of the encounter. When using MDM, the documentation must support a high level across two of three specific elements.
Medical Decision Making (MDM)
The first element is the number and complexity of problems addressed, which must be extensive. This often involves patients with multiple chronic illnesses who are experiencing acute exacerbations or severe complications.
The second element is the amount and complexity of data reviewed and analyzed during the visit. To meet the high threshold, this typically requires review of extensive testing, independent interpretation of tests (like a chest X-ray or EKG), or discussion of the case with an external physician or specialist.
The third component is the high risk of complications, morbidity, or mortality. This means the patient faces a significant probability of major complications, disability, or death without intensive intervention. Examples include managing a patient on high-risk medications or considering a major surgical procedure.
Time-Based Documentation
Alternatively, the provider can justify the use of 99233 by documenting that the total time spent on the date of the encounter met or exceeded the minimum time threshold. For this code, the total time must be 50 minutes or more on the calendar date of the service. This time includes both face-to-face time with the patient and non-face-to-face activities performed by the physician or other qualified healthcare professional. Included activities are:
- Preparing to see the patient.
- Obtaining a history.
- Performing an examination.
- Counseling the patient or family.
- Preparing orders.
- Reviewing tests.
- Documenting the encounter.
Billing Context and Appropriate Use
The use of CPT 99233 is governed by specific administrative rules. As a “per diem” service, the code can generally be reported only once per patient per day by the same physician or by any physician of the same specialty within the same group practice. This prevents multiple providers from billing for the same daily service. The determination of whether a visit is “subsequent” depends on whether the patient has already received a professional service from a physician of the exact same specialty and subspecialty within that group during the current hospital stay.
When multiple specialists are involved in a patient’s care, each specialist may report a subsequent hospital care code, provided they are managing different, distinct problems that require their unique expertise. In academic or teaching hospital settings, a teaching physician must ensure their personal involvement is clearly documented to support the high complexity of the service. The proper application of this code requires that the patient is physically present in the hospital inpatient or observation setting on the date the service is rendered. Accurate use of 99233 requires meticulous documentation that aligns with the high-complexity criteria, supporting the medical necessity of the intense service provided.