What Is the UB-04 Form in Medical Billing?
The UB-04 form — officially called the CMS-1450 — is the standard institutional claim form used by hospitals, skilled nursing facilities (SNFs), hospices, rehabilitation centers, and home health agencies to bill Medicare, Medicaid, and commercial payers for facility-based services.
Developed and maintained by the National Uniform Billing Committee (NUBC) and adopted by the Centers for Medicare & Medicaid Services (CMS), the UB-04 replaced the older UB-92 form to create a unified standard for institutional billing across the U.S. healthcare system. It contains 81 Form Locator (FL) fields that capture everything payers need to adjudicate institutional claims — patient demographics, diagnosis codes, revenue codes, discharge status, occurrence codes, and provider information.
Unlike the CMS-1500 used by individual physicians and clinics, the UB-04 is purpose-built for organizations managing multi-department services, bundled facility charges, extended inpatient stays, and complex revenue reporting. Claims can be submitted as paper (CMS-1450) or electronically via the 837I EDI format — the HIPAA-compliant digital equivalent.
Important: A single error on a UB-04 — an incorrect revenue code, wrong Type of Bill, or missing discharge status — can result in claim denial, delayed reimbursement, or a compliance audit. Accurate UB-04 billing directly protects your revenue.
Important: A single error on a UB-04 — an incorrect revenue code, wrong Type of Bill, or missing discharge status — can result in claim denial, delayed reimbursement, or a compliance audit. Accurate UB-04 billing directly protects your revenue.What You’ll Learn in This Guide:
- Which healthcare facilities use the UB-04 form
- Critical UB-04 Form Locators every biller must know
- The most common UB-04 billing errors and how to avoid them
- UB-04 vs. CMS-1500: Key differences
- 837I electronic submission overview
- Frequently asked questions (AI search & Google featured snippet ready)
Which Healthcare Facilities Use the UB-04 Form?
The UB-04 is not for every provider. It applies to institutional facilities — those billing under a facility tax ID — rather than individual practitioners.
| Facility Type | Uses UB-04? | Key Notes |
|---|---|---|
| Acute Care Hospital |  Yes | Inpatient and outpatient facility billing |
| Skilled Nursing Facility (SNF) | Yes | Medicare Part A and post-acute care |
| Inpatient Rehabilitation Facility | Yes | Stroke, orthopedic, neuro rehab claims |
| Hospice Care Provider | Yes | Medicare hospice benefit billing |
| Home Health Agency (HHA) | Yes | OASIS-based visit claims under Medicare |
| Behavioral Health Hospital | Yes | Psychiatric admissions and substance use |
| Long-Term Care Hospital (LTCH) | Yes | Extended stays typically over 25 days |
| Ambulatory Surgery Center (hospital-owned) | Sometimes | Only when part of a hospital system |
| Physician Clinic / Private Practice |  No | CMS-1500 form is used instead |
Critical UB-04 Form Locators Every Biller Must Know
The UB-04’s 81 Form Locators are grouped by function. The following fields have the greatest direct impact on claim acceptance, payer adjudication, and reimbursement accuracy.
Type of Bill (FL 4)
A 3-digit code that tells payers the facility type, service classification, and billing frequency. For example, 111 = Hospital Inpatient Original Claim; 131 = Hospital Outpatient Original Claim; 331 = Skilled Nursing Facility Inpatient Original Claim. An incorrect TOB is one of the leading causes of claim misrouting and outright rejection.
Revenue Codes (FL 42)
4-digit codes that identify the department or service category generating the charge — for example, 0250 (Pharmacy), 0300 (Laboratory), 0420 (Physical Therapy), 0450 (Emergency Room). Revenue codes must align precisely with the HCPCS/CPT codes entered in FL 44, or payers will suspend or deny the claim.
Principal Diagnosis Code (FL 67)
The ICD-10-CM code for the primary condition driving the patient’s care. This field directly determines DRG (Diagnosis Related Group) grouping for Medicare inpatient reimbursement. An invalid or truncated code here leads to grouping failure and significant underpayment.
Discharge Status (FL 17)
Indicates the patient’s disposition at the end of services: 01 = Discharged to home; 02 = Transferred to another inpatient facility; 20 = Expired. This field affects DRG payment calculations and post-acute care reimbursement. Incorrect status codes are a major audit trigger.
Occurrence Codes & Dates (FL 31–34)
Capture significant billing events — accident dates, symptom onset, Medicaid eligibility start dates, and similar qualifying events. Missing or incorrect occurrence codes frequently delay payment or cause direct denials, especially on Medicare and Medicaid claims.
Attending Provider NPI (FL 76)
Required on virtually all UB-04 claims. This field must contain the individual NPI of the attending physician, never the facility NPI. Substituting the facility NPI for the individual clinician’s NPI is a top rejection trigger across all payer types.
Most Common UB-04 Billing Errors — And How to Fix Them
| Error Type | Claim Impact | How to Prevent It |
|---|---|---|
| Wrong Type of Bill (FL 4) | Misrouted or rejected claim | Verify 3-digit TOB against payer policy per visit type and frequency |
| Revenue code/HCPCS mismatch (FL 42 & 44) | Suspension or denial | Follow payer-specific revenue code-to-HCPCS crosswalks |
| Invalid ICD-10 code (FL 67) | DRG grouping failure, medical necessity denial | Use updated ICD-10-CM codes and validate before submission |
| Incorrect discharge status (FL 17) | Overpayment, audit risk | Match discharge status to the clinical record and post-acute plan |
| Missing occurrence or condition codes | Payment delay or suspension | Review payer billing instructions for every care setting |
| Facility NPI in attending provider field (FL 76) | Hard rejection | Always use the individual clinician’s NPI in FL 76–79 |
| Inconsistent service dates (FL 6 vs FL 45) | Audit flag, suspicious billing | Reconcile Statement Period with individual service dates |
Pro Tip: Use billing software with built-in UB-04 claim scrubbers. Monitor your Remittance Advice (RA) regularly to catch denial pattern trends before they compound into revenue loss.
UB-04 vs. CMS-1500: Key Differences
Many practices operate in both institutional and professional billing environments. Knowing which form applies prevents costly submission errors and payer rejections.
| Criteria | UB-04 (CMS-1450) | CMS-1500 (HCFA) |
|---|---|---|
| Used For | Hospitals, SNFs, hospices, institutional facilities | Physicians, clinics, individual providers |
| Maintained By | National Uniform Billing Committee (NUBC) | National Uniform Claim Committee (NUCC) |
| Number of Fields | 81 Form Locators | 33 Fields |
| Electronic Equivalent | 837I (Institutional) | 837P (Professional) |
| Medicare Applicability | Medicare Part A | Medicare Part B |
| Typical Payers | Medicare, Medicaid, commercial facility plans | Medicare, Medicaid, commercial provider plans |
UB-04 and 837I Electronic Claim Submission
The 837I is the HIPAA-compliant EDI version of the UB-04 form. Facilities transmit 837I files through clearinghouses — such as Availity, Change Healthcare, or Office Ally — or via direct EDI connections to Medicare Administrative Contractors (MACs), state Medicaid programs, and commercial payers.
Why 837I matters for your revenue cycle:
- Faster reimbursement — Electronic claims process days ahead of paper submissions
- Built-in validation — Clearinghouses flag errors before claims reach payers
- Claim tracking — 999 and 277CA acknowledgment files confirm receipt and surface issues immediately
- Batch submission — Submit large volumes of institutional claims simultaneously
- Full HIPAA compliance — Secure, auditable transmission that satisfies regulatory requirements
Most modern EHR and RCM platforms (Kareo, AdvancedMD, eClinicalWorks) support 837I generation natively. A billing partner that actively monitors acknowledgment files, resubmits rejections promptly, and tracks ERA patterns will protect your institutional revenue at every stage.
Stop Losing Revenue on UB-04 Claim Errors — Beeline Medical LLC Is Here to Help
At Beeline Medical LLC, we provide expert institutional and professional medical billing services to healthcare facilities across the United States — from our headquarters in Maryland Heights, Missouri. Our certified billing professionals handle every stage of the UB-04 revenue cycle: patient data capture, accurate ICD-10 and revenue coding, 837I electronic submission, denial management, and payer-specific compliance.
Whether you operate an acute care hospital in St. Louis, a behavioral health facility in Kansas City, or a home health agency anywhere in the country, Beeline Medical delivers a 99% clean claim acceptance rate, complete UB-04 compliance, and faster reimbursements — with no lock-in contracts.
Frequently Asked Questions About the UB-04 Form
What is the UB-04 form used for in medical billing?
The UB-04 (CMS-1450) is used to submit institutional claims for hospital, SNF, hospice, rehabilitation, and home health services to Medicare Part A, Medicaid, and commercial insurers. It contains 81 Form Locators that capture all data needed for facility-level reimbursement.
What is the difference between UB-04 and CMS-1500?
The UB-04 is for institutional providers (hospitals, SNFs, hospices) while the CMS-1500 is for professional providers (physicians, clinics). They use different fields, have different electronic equivalents (837I vs. 837P), and apply to different Medicare parts (Part A vs. Part B).
What are revenue codes on the UB-04 form?
Revenue codes are 4-digit numbers entered in FL 42 that identify the department or service type responsible for the charge. Common examples include 0300 (Laboratory) and 0450 (Emergency Room). They are required for Medicare and Medicaid DRG and APC payment grouping.
Can UB-04 claims be submitted electronically?
Yes. The electronic equivalent of the UB-04 is the 837I EDI file, submitted through approved clearinghouses or direct EDI payer connections. Electronic submission is faster, more accurate, and required by most major payers today.
What is a Type of Bill (TOB) on the UB-04?
The Type of Bill is a 3-digit code in FL 4 that identifies the facility type, service classification, and billing frequency. It determines how payers route and adjudicate the claim. An incorrect TOB is one of the most common causes of claim rejection.
Who maintains the UB-04 form?
The UB-04 is maintained by the National Uniform Billing Committee (NUBC) and adopted by the Centers for Medicare & Medicaid Services (CMS) for standardized institutional billing across the United States.
What are the most common UB-04 billing errors?
The most frequent errors include incorrect Type of Bill, revenue code and HCPCS mismatches, invalid or outdated ICD-10-CM codes, incorrect discharge status, missing occurrence or condition codes, and using a facility NPI where the attending physician’s individual NPI is required.
How does UB-04 billing affect DRG reimbursement?
The diagnosis and procedure codes entered on the UB-04 — especially in FL 67 (Principal Diagnosis) and FL 74 (Principal Procedure) — determine which Diagnosis Related Group (DRG) a Medicare inpatient claim groups into. Accurate coding directly determines the reimbursement amount for inpatient hospital stays.