How should length of stay be treated differently in inpatient versus outpatient coding?

• A. Inpatient coding focuses on the encounter only
• B. Inpatient coding uses diagnosis and procedure codes for the stay; outpatient coding focuses on the encounter or service provided, not length of stay
• C. Inpatient coding uses only CPT codes
• D. Inpatient coding ignores diagnoses

Answer: (B)

The main idea is that the setting of care determines how length of stay influences coding. In inpatient coding, the entire hospitalization is coded with both diagnoses and procedures to reflect what happened during the stay, and the length of that stay can drive the complexity of the case and the DRG-based payment. In outpatient coding, the focus is on the individual service or encounter provided on a specific date, coded with CPT/HCPCS for the services and ICD-10-CM for any diagnoses documented; the length of stay isn’t used to determine payment for a single outpatient encounter. That’s why the statement describing inpatient coding as using diagnosis and procedure codes for the stay, while outpatient coding centers on the encounter or service and not length of stay, is the correct one. The other options misstate how inpatient coding works—whether it omits diagnoses, relies only on CPT codes, or ignores the stay entirely.