Introduction to Inpatient Coding & DRGs

For an admitted patient, the hospital's payment for the whole stay is mostly fixed by the MS-DRG (Medicare Severity Diagnosis-Related Group) — not by each service. The DRG is calculated from: • the principal diagnosis, • secondary diagnoses (complications/comorbidities), • ICD-10-PCS procedures, • discharge status, age, sex.

So inpatient coders focus on complete, accurate diagnosis and procedure capture — that directly drives payment and quality statistics.