A UB-04 form (also known as the CMS-1450 form) is the main billing form that hospitals and medical facilities use to get paid by insurance companies. Think of it as the “official bill” a facility sends to Medicare, Medicaid, and commercial insurance plans after treating a patient.
If a patient gets services like surgery, inpatient care, ER treatment, rehab, outpatient procedures, or even home health care, the facility uses the UB-04 form to list what was done and how much it costs. Insurance companies then review this form to decide how much they will reimburse.
It’s designed to be a standard format, meaning every hospital fills it out the same way. This makes it easier for insurance companies to process claims quickly and avoid confusion.
Who Uses the UB-04 Form?
The UB-04 form is mainly used by hospitals and large medical facilities—not by individual providers. Any healthcare organization that bills for facility-based services relies on this form to submit claims to insurance companies.
Here are the most common users:
Hospitals (Inpatient & Outpatient)
They use the UB-04 to bill for room charges, surgeries, labs, imaging, ER visits, and more.
Ambulatory Surgery Centers (ASCs)
ASCs use it to bill for outpatient procedures like scopes, orthopedic surgeries, pain management, etc.
Skilled Nursing Facilities (SNFs)
SNFs submit UB-04 forms for long-term care, rehab stays, and therapy services.
Home Health Agencies
They use it to bill for nursing visits, therapy, and care provided at the patient’s home.
Rehabilitation Centers
Both inpatient and outpatient rehab programs rely on the UB-04 format.
Hospice Providers
They use it to bill for end-of-life care services.
UB-04 vs. CMS-1500: What’s the Difference?
Many providers get confused about when to use the UB-04 and when to use the CMS-1500—but the difference is actually very simple.
UB-04 = Facility Billing
The UB-04 form is used by hospitals and facilities to bill for institutional services such as:
- ER visits
- Inpatient stays
- Outpatient procedures
- Lab, imaging, and surgery are done inside a facility
Facilities use this form because the services involve facility fees, bed charges, equipment usage, and multiple departments.
CMS-1500 = Professional Billing
The CMS-1500 form is used by individual providers, such as:
- Physicians
- Nurse practitioners
- Therapists
- Mental health providers
- Independent billers
This form is for professional services, meaning the provider’s time, expertise, and direct patient care.
The easiest way to remember:
- If the claim comes from a building, use UB-04.
- If the claim comes from a person, use CMS-1500.
Both forms are essential in medical billing, but each has a different purpose—and using the wrong one can delay or even deny a claim.
Key Fields You Must Complete on the UB-04 Form
| UB-04 Field | Description |
| Patient Information (Fields 8–17) | Includes patient’s name, address, DOB, and insurance details. Accuracy is crucial to prevent denials. |
| Type of Bill (Field 4) | Indicates the facility type and type of claim (inpatient, outpatient, corrected claim, etc.). Correct coding ensures proper claim processing. |
| Revenue Codes (Field 42) | Shows the category of services provided (room, lab, ER, surgery, imaging, etc.). Must match procedure codes for proper payment. |
| HCPCS/CPT Codes (Field 44) | Represents the specific procedures performed. Correct codes and modifiers ensure accurate reimbursement. |
| Service Dates (Field 6 & 45) | Admission, discharge, and service dates. Errors here are a common reason for claim rejections. |
| Diagnosis Codes (Field 67) | Lists the principal and secondary diagnoses explaining why care was provided. Correct placement affects payment. |
| Total Charges (Field 47) | Total amount billed for all services. Should match the sum of itemized charges. |
| NPI & Taxonomy (Fields 56, 81) | Identifiers for the facility and the rendering provider. Missing or incorrect NPIs can lead to claim denials. |
Common UB-04 Mistakes Providers Should Avoid
Even small errors on a UB-04 form can cause delays or denials. Here are the most common mistakes providers make:
- Incorrect Type of Bill (TOB): Using the wrong code can stop the claim from being processed.
- Wrong Revenue Codes: Revenue codes must match the services provided and the procedure codes.
- Missing or Invalid NPI: Both facility and provider NPIs are required for claim approval.
- Mismatched Diagnosis/Procedure Codes: The diagnosis codes must support the procedures billed.
- Incomplete Patient Information: Missing DOB, insurance ID, or plan details often results in claim rejections.
- Errors in Service Dates: Admission, discharge, or procedure dates that don’t match the medical record can delay payment.
Double-checking these areas before submission can save time, reduce rework, and help claims get paid faster.
How to Fill Out a UB-04 Form Correctly
Filling out the UB-04 form doesn’t have to be complicated if you follow the key steps. Here’s a simple approach for providers and facility billing teams:
- Gather Patient & Insurance Information
Make sure you have accurate patient details, insurance plan info, and any prior authorizations. - Assign Diagnosis and Procedure Codes
Use ICD-10 for diagnoses and CPT/HCPCS for procedures. Make sure they match the services provided. - Add Revenue Codes and Charges
Break down charges by service type (room, lab, imaging, surgery). Verify that each revenue code aligns with the procedure code. - Validate NPIs and Taxonomy Codes
Include the facility NPI and the rendering provider NPI, along with taxonomy codes if required by the payer. - Check Service Dates
Confirm admission, discharge, and service dates are correct and match medical records. - Review Total Charges
Make sure the total amount billed equals the sum of all itemized charges. - Submit the Claim
Send electronically via clearinghouse or submit a paper claim if necessary. Double-check for completeness to reduce denials.
By following these steps, providers can minimize errors and ensure claims move smoothly through the insurance process.