Place of Service 21 (Inpatient Hospital)
Place of service code for services furnished to a patient who has been admitted as an inpatient at a hospital.
1 min read · Last reviewed May 23, 2026
At a glance
- Category
- Billing
- Primary sources
- 2
- Workspace handoff
- revenue audit →
Where this comes up
This shows up in revenue-cycle work — claim scrubbing, charge entry, posting, A/R follow-up, and month-end close. Billers and practice managers hit this term when reconciling a payment, working a denial queue, or auditing why a claim aged past 60 days.
Full definition
What it is in practice
CMS POS POS 21 identifies inpatient professional services. The corresponding hospital facility bill goes under MS-DRG.
How it shows up in your practice
Set EHR encounter templates correctly for inpatient rounding. POS mismatches between professional and facility claims cause downstream issues.
Sources
- CMS — Place of Service Code Sethttps://www.cms.gov/medicare/coding-billing/place-of-service-codes/code-sets
- CMS — Place of Service Codes Listhttps://www.cms.gov/medicare/coding-billing/place-of-service-codes/code-sets
Audit inpatient POS in Revenue Audit
Open revenue audit →Related terms
- BillingPlace of Service (POS) CodeTwo-digit code on a CMS-1500 claim identifying where a service was provided.
- BillingInpatient Hospital BillingFacility billing for hospitalized patients, classified using the MS-DRG system under the Acute Inpatient Prospective Payment System.
- BillingMS-DRGMedicare Severity Diagnosis Related Groups — the classification system used to pay inpatient hospital admissions under Medicare's prospective payment system.
D3rx is a healthcare-billing and compliance research aid maintained by D3rx Inc. Articles are drafted by an LLM (Anthropic Claude) against primary HHS, OCR, CMS, eCFR, NIST, and state-regulator publications, and reviewed for restraint and source fidelity by the D3rx team.
Reviewer status: a named credentialed reviewer (CHC, CHPC, or healthcare attorney) is being engaged. Until that engagement is finalized, this page does not claim credentialed review.
Related across the archive
- GlossaryPlace of Service (POS) CodeTwo-digit code on a CMS-1500 claim identifying where a service was provided.
- GlossaryInpatient Hospital BillingFacility billing for hospitalized patients, classified using the MS-DRG system under the Acute Inpatient Prospective Payment System.
- GlossaryMS-DRGMedicare Severity Diagnosis Related Groups — the classification system used to pay inpatient hospital admissions under Medicare's prospective payment system.
- GlossaryPlace of Service 11 (Office)Place of service code for services furnished in a physician's office or other freestanding outpatient setting.
- GlossaryTelehealth POS Codes (02 and 10)Place of Service 02 (telehealth other than home) and POS 10 (telehealth in patient's home) identify telehealth encounters on professional claims.
- BillingAWV + Problem Visit Same Day: How to Bill CorrectlyYes, you can bill AWV and a problem visit the same day. Here's how to do it correctly with modifier -25.
- BillingPlace of Service Codes: Which One to Use and Why It Changes Your ReimbursementPOS 11 vs 21 vs 02 vs 10. How the two-digit code on your claim determines whether you get office or facility rates.
- BillingUB-04 Billing: Bill Types, Revenue Codes, and Occurrence Codes ExplainedBill type 111 vs 131, revenue code 0250, occurrence span code 70. Every UB-04 field explained in plain English.
This glossary entry is a research aid for billing and compliance staff. It does not provide legal, medical, or financial advice and does not replace counsel. References cited link to primary sources at HHS, OCR, CMS, eCFR, NIST, and the relevant payer or industry body.