Revenue Code 0450: Emergency Room, General Classification
Revenue code 0450 is the general emergency room code in UB-04 form locator 42. A hospital reports it on an outpatient claim line when the patient was seen in its emergency department and no narrower emergency code describes the charge.
Written by Salman Saeed, CEO and Co-Founder · Reviewed by a Certified Medical Coder · Last reviewed October 2026In short: 0450 is the default emergency department revenue code on a hospital outpatient claim. Medicare wants an HCPCS code on the line, a line item date equal to the day the patient entered the ER, and a reason for visit on the claim. The code is blocked on type of bill 012x.
What Does Revenue Code 0450 Mean?
The NCHS codebook for Medicare outpatient revenue center values labels 0450 as emergency room, general classification. It heads a family of five emergency room values: 0450, 0451, 0452, 0456 and 0459.
A revenue code is a four-digit entry in form locator (FL) 42 of the UB-04 that tells the payer which department or service line a charge belongs to. The NUBC owns the code set and sells the manual, so this page paraphrases it.
| Question | Answer for 0450 |
|---|---|
| Where it is entered | UB-04 FL 42, with the charge in FL 47 on the same line |
| Electronic claim | 837I (institutional claim) |
| Bill types named in Medicare rules | 013x hospital outpatient and 085x critical access hospital |
| Bill type where Medicare blocks it | 012x hospital Part B inpatient services |
When Do You Use 0450, and When Something Else?
Use 0450 for the general emergency department charge. Section 180.6 of Chapter 4 says emergency room services from hospital outpatient departments, whether paid under OPPS or not, are reported under the 045x revenue codes. If a narrower code describes the line, such as 0451 for the EMTALA screening or 0456 for urgent care, the narrower code is the better fit.
Procedures done in the ER need their own line. Since July 1, 2001, CMS has required a separate charge for the ER visit and for surgical procedures, and the procedure charge goes under the emergency room revenue code. Several procedures in one session can share one charge on one procedure line.
| Date of service | Revenue code | HCPCS | Modifier | Charge |
|---|---|---|---|---|
| 7/5/2001 | 0450 | 99283 | 25 | $150 |
| 7/5/2001 | 0450 | 12011 | $300 | |
| 7/5/2001 | 0450 | 12035 | ||
| 7/5/2001 | 0250 | $70 | ||
| 7/5/2001 | 0270 | $85 |
How Do Dates, Units and Reason for Visit Work?
The line item date for the ER encounter is the date the patient entered the ER, even if the stay runs across midnight. Related lab and radiology lines carry the date each service was rendered.
Chapter 25 requires a single line item date of service for every iteration of every revenue code on outpatient bills such as 013x. Critical access hospitals are excepted from that line-date requirement.
Any claim on type of bill 013x or 085x that carries a 045x code, 0516 or 0762 needs the patient's reason for visit in FL 70A to 70C when the priority of visit in FL 14 is code 1, 2 or 5. Chapter 25 states this rule for the whole 045x family, so it applies to 0450.
Hospital outpatient lines from an off-campus provider-based emergency department that meets the dedicated emergency department test also need HCPCS modifier ER on every line with a CPT or HCPCS code. Critical access hospitals are not required to report it, and it does not affect payment (section 20.6.18).
Which HCPCS Codes Go with 0450?
Chapter 4, section 20.1 says acute care hospitals must report HCPCS codes, so a 0450 line carries the visit code. Section 160 has Type A emergency departments bill CPT 99281 to 99285 and Type B departments bill G0380 to G0384. Section 160 says the facility level comes from the hospital's own written guidelines.
Typical pairs run from 99281 to 99285, including 99283. The physician's own work goes on a separate CMS-1500, covered on emergency medicine billing. Level assignment for the facility is explained at ED facility level coding.
How Is a 0450 Line Paid?
Section 160 says emergency department and clinic visits are paid separately in some cases and as part of a composite APC payment in others. The mechanics are in OPPS and APCs.
Where Does Revenue Code 0450 Sit on the Claim, and What Does the Remittance Show?
FL 42 holds 0450 on the emergency visit line, with the E/M code in FL 44. Each revenue code line needs its own date in FL 45.
On the remittance, a CO-16 or CO-4 on a 0450 line points to FL 44, not the revenue code.
An ED claim has 0450 with 99285 for $1,100.00 and 0450 with 12011 for $240.00.
Why Do 0450 Lines Get Denied?
| Code | What X12 says | Where it shows up on a 0450 line |
|---|---|---|
| CO-16 with RARC M51 | Claim or service lacks information or has a billing error; M51 is missing, incomplete or invalid procedure code | The line has 0450 and no HCPCS code |
| CO-97 | The benefit is included in the payment for another service already adjudicated | A procedure or ancillary line packaged into the visit payment |
| CO-4 | The procedure code is inconsistent with the modifier used | Modifier 25 or ER missing, extra or mismatched on the line |
| PR-96 with RARC M28 | Non-covered charge; M28 says it does not qualify for payment under Part B when Part A coverage is exhausted or not available | A 045x line on a 012x bill, which Medicare edits against |
If these denials keep coming back, our denial management team can work them. For the full facility workflow see hospital and facility billing.
Related Codes
- Restricted-use Linked NCHS-CMS Medicare Data: Outpatient Revenue Center codebook · CDC / NCHS
- Medicare Claims Processing Manual, Chapter 25: Completing and Processing the Form CMS-1450 Data Set · CMS
- Medicare Claims Processing Manual, Chapter 4: Part B Hospital (Including Inpatient Hospital Part B and OPPS) · CMS
- 42 CFR 489.24, Special responsibilities of Medicare hospitals in emergency cases · eCFR
- How to identify hospital claims for emergency room visits in Medicare claims data · ResDAC
- Claim Adjustment Reason Codes · X12
- Remittance Advice Remark Codes · X12
- Medicare Claims Processing Manual, chapter 25, section 75 (UB-04 form locators 42 and 44) · CMS
- Medicare Claims Processing Manual, chapter 22, sections 60.1 to 60.3 (group codes, CARC, RARC on the remittance) · CMS
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Common Questions
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01What is revenue code 0450 used for?
It reports general emergency room charges on a UB-04 outpatient claim. Medicare's manual says ER services from hospital outpatient departments are reported under the 045x codes. Use 0450 when no narrower code such as 0451 for EMTALA screening or 0456 for urgent care fits the line.
02Which CPT codes go with revenue code 0450?
Type A emergency departments report visits with CPT 99281 to 99285. Type B emergency departments report them with G0380 to G0384. Procedures done in the ER, such as a laceration repair, ride on the same revenue code with their own CPT code, as Chapter 4 section 180.2 shows.
03Can revenue code 0450 go on a CMS-1500?
No. Revenue codes belong to UB-04 form locator 42 and the 837I institutional claim. The physician's professional service goes on a CMS-1500 with a CPT code and a place of service, which is 23 for a hospital emergency room in the CMS place of service list.
04What date goes on a 0450 line if the patient is there past midnight?
The date the patient entered the ER. Chapter 4 section 180.6 says the ER encounter line carries that date even if the visit spans several dates. Related lab and radiology lines carry the date each service was actually rendered, not the entry date.
05Do I need an HCPCS code on the 0450 line?
Yes for Medicare. Chapter 4 section 20.1 requires acute care hospitals to report HCPCS codes, and CMS's own example shows 0450 beside 99283 and the repair codes. A 0450 line with no code is the usual cause of a CO-16 with RARC M51 return.
06Why was my 045x line rejected on a 012x bill?
Chapter 4 section 240.1 lists 045x among the revenue codes Medicare edits against on type of bill 012x, which is hospital Part B inpatient billing. The remittance carries group code PR, CARC 96 and RARC M28. Check whether the claim belongs on 013x instead.
ER Lines Coming Back from the Payer?
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