Place of service code · CMS
POS 23: emergency room, hospital.
POS 23 is the CMS place of service code for "a portion of a hospital where emergency diagnosis and treatment of illness or injury is provided." It goes in the place of service field of a professional claim when the patient was seen in a hospital emergency room. An urgent care center that is separate from a hospital emergency room uses POS 20 instead.
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What CMS says POS 23 means
A portion of a hospital where emergency diagnosis and treatment of illness or injury is provided.
Code name: Emergency Room - Hospital. Source: CMS Place of Service Codes for Professional Claims, retrieved 2026-11-02.
How POS 23 differs from the settings around it
- POS 20, urgent care: CMS defines it as a location "distinct from a hospital emergency room, an office, or a clinic" for unscheduled, ambulatory patients seeking immediate attention. If the site is not a hospital emergency room, 23 does not fit.
- POS 22, on-campus outpatient hospital: a portion of a hospital's main campus providing diagnostic, therapeutic and rehabilitation services to patients who do not require hospitalization. Emergency care has its own code, 23.
- POS 21, inpatient hospital: for patients admitted to the hospital.
- POS 19, off-campus outpatient hospital: a provider-based department away from the main campus, not an emergency room code.
Why emergency rooms are treated differently
Hospitals with an emergency department have a federal screening duty. Under 42 CFR 489.24(a)(1), when an individual comes to the emergency department the hospital must provide an appropriate medical screening examination to determine whether an emergency medical condition exists and, if one does, stabilizing treatment or an appropriate transfer. That duty attaches to the hospital emergency department. It does not decide how a given payer reimburses a POS 23 claim.
What to check before you submit
- Where was the patient physically seen: an emergency room of a hospital, or a freestanding urgent care or clinic? Use the place the service was furnished.
- If the denial or edit shows a place of service mismatch, compare the POS on the claim with the procedure code's allowed settings in the payer's policy.
- CMS tells billers to check with individual payers, such as Medicare, Medicaid and private insurers, for reimbursement policies for each code. Do not assume one payer's treatment of POS 23 applies to another.
- If the claim used the wrong POS, correct it and resubmit as the payer directs. For Medicare, a party can ask the contractor to reopen within 1 year for any reason (42 CFR 405.980(c)), and the claim filing limit in 42 CFR 424.44 still applies.
Worked example (hypothetical)
A clinician evaluates a patient in a hospital's emergency department on Saturday night. The place of service is 23. The same clinician sees a patient the next morning at a standalone walk-in center not attached to a hospital: that is 20, or 11 if it meets the CMS definition of an office. Reusing 23 for the second visit would misstate where the service was provided.
Sources
- CMS: Place of Service Codes for Professional Claims — code names and descriptions (retrieved 2026-11-02)
- eCFR: 42 CFR 489.24 (EMTALA screening) — regulation text as of the eCFR issue dated 2026-10-29, retrieved 2026-11-02
- eCFR: 42 CFR 405.980 — regulation text as of the eCFR issue dated 2026-10-29, retrieved 2026-11-02
- eCFR: 42 CFR 424.44 (time limits for filing claims) — regulation text as of the eCFR issue dated 2026-10-29, retrieved 2026-11-02
Every code description and rule above was retrieved from these pages on November 2, 2026. X12 code text is copyrighted by X12 and quoted only for the codes explained here; the complete lists are at x12.org. Payers revise code lists, contracts and policies, so confirm anything that affects a claim or a deadline with the payer.
Frequently asked questions
What is POS 23?
POS 23 is the CMS place of service code for Emergency Room - Hospital: a portion of a hospital where emergency diagnosis and treatment of illness or injury is provided.
Is urgent care POS 23?
No. CMS defines urgent care as POS 20, a location distinct from a hospital emergency room, an office or a clinic. POS 23 is for a hospital emergency room.
Does POS 23 mean the claim is an emergency claim?
The code names the setting, a hospital emergency room. Whether the payer treats the service as emergency care is decided by the payer's own rules, and CMS says to check each payer for how it reimburses each code.
Not legal, billing or medical advice
This page explains published code lists and rules and runs a lookup in your browser. It cannot see your claim, your contract or any payer's policy. Confirm with the payer or your Medicare Administrative Contractor before you resubmit, appeal or bill a patient.