Current Procedural Terminology (CPT) codes are a standardized language used across the healthcare industry to communicate the services provided by physicians and other qualified healthcare professionals. These five-digit codes are the foundation of medical billing, ensuring that payers and providers agree on the exact nature of the service delivered. The 9923x series of codes specifically relates to “Subsequent Hospital Care,” which covers the daily management of a patient already admitted to the inpatient or observation setting. CPT code 99233 represents the highest complexity and intensity of service a physician can bill for a daily hospital visit within this series.
The Official Description and Context
CPT code 99233 is defined as a visit for subsequent hospital inpatient or observation care provided on a single calendar day. This code is designated for the evaluation and management of a patient whose condition requires a medically appropriate history and examination, along with a high level of medical decision making (MDM). The service is considered “subsequent” because it occurs after the physician’s initial admission assessment and does not include the day of discharge.
The 99233 code is used once per day by the primary physician overseeing the patient’s care, regardless of how many times the patient is seen. Its application covers the necessary daily reassessment, review of new data, adjustment of treatment plans, and coordination of care that occurs in the inpatient environment. Since 2023, the description for this code has been harmonized to apply equally to both the hospital inpatient and observation care settings.
The physician or qualified healthcare professional has the flexibility to select this code based on one of two criteria: either the complexity of the MDM or the total time spent on the encounter. When time is the determining factor, the total time spent on the patient’s care must meet or exceed a specific threshold. This flexibility acknowledges that the intensity of a hospital visit may stem from either high clinical complexity or the sheer time required for comprehensive management.
Key Documentation Requirements
To justify billing CPT 99233, the documentation must support either a high level of Medical Decision Making (MDM) or a total time of at least 50 minutes spent on the patient’s care on the date of the encounter. For MDM selection, the requirements for two out of the three MDM elements must be met at the “High” complexity level. These three elements are the number and complexity of problems addressed, the amount and complexity of data reviewed and analyzed, and the risk of complications and/or morbidity or mortality from patient management.
Number and Complexity of Problems
This element is met at the high level when the patient presents with one or more chronic illnesses experiencing a severe exacerbation, progression, or side effects of treatment. An example is managing a patient with acute myocardial infarction or severe respiratory distress that poses a threat to life or bodily function.
Amount and/or Complexity of Data
This element is satisfied when the documentation shows an extensive need to review and analyze data. This includes meeting the requirements of three categories of data, such as ordering and reviewing unique tests, independently interpreting a test performed by another professional, and reviewing notes from an external source or obtaining a history from an independent historian. This signifies a high volume of information the provider must synthesize.
Risk of Complications
This element reaches the high level when the management options themselves carry a substantial risk. This includes decisions regarding emergency major surgery or the administration of drug therapy that necessitates intensive monitoring for toxicity, such as certain chemotherapy agents or antiarrhythmic medications. The documentation must clearly reflect the high probability of serious adverse outcomes.
Alternatively, the physician may choose to use total time on the date of the encounter to select the code. For CPT 99233, the provider must document a cumulative total of at least 50 minutes spent performing medically necessary work. This total time includes both face-to-face activities with the patient and non-face-to-face tasks performed on that day, such as reviewing the electronic health record, coordinating care with other specialists, and documenting the encounter.
Distinguishing the High-Level Service
CPT 99233 stands apart from the lower-level subsequent hospital care codes, 99231 and 99232, based primarily on the required intensity of the service. CPT 99231 is reserved for the management of a patient who is stable, recovering, or improving, requiring only straightforward or low complexity MDM. This typically involves a patient whose treatment plan is working well and needs minimal adjustment.
CPT 99232 is utilized for patients whose status is less predictable, perhaps responding inadequately to therapy or developing a minor complication, necessitating moderate complexity MDM. The patient’s condition often requires the consideration of a new diagnosis or the addition of a new medication, but without the immediate threat to life seen in the highest level. The time requirement for the moderate-level code, for comparison, is 35 minutes.
In contrast, CPT 99233 is appropriate for a patient who has developed a significant complication, has a substantial new problem, or remains unstable, requiring the highest level of clinical judgment and resource utilization. The patient’s clinical scenario warrants a decision that carries a high risk of morbidity or mortality, such as deciding to transfer the patient to the Intensive Care Unit or initiating an urgent, high-risk procedure. The difference between the codes is fundamentally the degree of patient instability and the corresponding weight of the physician’s medical decision.