For a patient in observation care, selecting the correct E/M codes requires evaluating each day's service level and the provider's documentation.

Day 1: The patient was admitted for observation, and the physician prescribed IV and SQ insulin, noting diabetes with hyperglycemia requiring complex management. The CPT® code 99235 is appropriate here because it represents an initial observation or inpatient care for patients with high-complexity medical decision-making (MDM), which aligns with the patient's unstable glucose and the management requirements.

Day 2: The patient's glucose levels improved, and the provider documented spending 25 minutes with the patient in continued observation care. Since this is an established patient with continued observation, 99231 applies here, indicating subsequent observation care with low MDM complexity.

Day 3: The provider documented spending 15 minutes with the patient, whose glucose levels normalized, and then discharged the patient from observation care. Code 99238 is used for a discharge from observation care and is selected based on discharge times under 30 minutes.

These codes were selected based on CPT® guidelines for observation care and the provider’s time-based documentation. This matches the medical decision complexity documented per the case and code descriptions available for observation care management.