UB-04 Form in Medical Billing: Complete 2025 Guide to CMS-1450, 837I Claims, and Institutional Billing Compliance
In facility-based healthcare billing, the UB-04 form is a cornerstone document, pivotal to the revenue cycle for institutional providers like hospitals, nursing homes, and rehabilitation centers. Also known as the CMS-1450 form, the UB-04 is the universal claim form used by institutional providers to bill services rendered to patients in inpatient and outpatient settings.
Unlike other CMS form, which is primarily used by individual healthcare providers and physicians, the UB-04 form is designed for hospitals, skilled nursing facilities, home health agencies, rehab centers, and other institutions that bill Medicare, Medicaid, TRICARE, and commercial payers.
Developed by the National Uniform Billing Committee (NUBC), the UB-04 is used for both paper claims and electronic submissions (via the 837I format) and ensures that medical claims are submitted in a standardized, payer-accepted layout.
Whether you are billing for a routine outpatient procedure or a complex inpatient hospital stay, mastering the UB-04 form is essential for ensuring timely reimbursement, claim acceptance, and revenue cycle efficiency.
In this MedStates UB-04 guide, we will walk you through everything you need to know—from field-by-field instructions and common denial codes to payer-specific requirements and billing best practices—so your facility can improve its clean claim rate and avoid costly errors.
Blog Outline
- What Is UB-04 Form in Medical Billing?
- Providers and Facilities That Use the UB-04
- Detailed Field-by-Field Explanation of UB-04 (Form Locator Boxes 1–81)
- Key Elements Unique to the UB-04 Form
- Most Common UB-04 Errors (and How to Prevent Them)
- UB-04 vs. CMS-1500 – Key Differences in Billing Forms
- UB-04 Billing Guidelines by Payer (Medicare, Medicaid, and Commercial)
- UB-04 in Electronic Claim Submission (837I File Format)
- Frequently Asked Questions on UB-04
What Is UB-04 Form in Medical Billing?
The UB-04 form, officially designated as the CMS-1450, is the standardized medical billing form used by institutional healthcare providers to submit claims for reimbursement. Introduced by the Centers for Medicare & Medicaid Services (CMS) in collaboration with the National Uniform Billing Committee (NUBC), the UB-04 replaced its predecessor (UB-92) to modernize and streamline billing across the U.S. healthcare system.
This form is specifically tailored for facilities that deliver inpatient, outpatient, and long-term care services, including:
Acute care hospitals
Skilled nursing facilities (SNFs)
Inpatient rehabilitation centers
Behavioral health institutions
Home health agencies
Hospice and long-term care facilities
Whereas individual healthcare practitioners bill using the CMS-1500 form, UB-04 is the institutional claim form designed for organizations that manage patient stays, use multiple departments, and generate complex billing scenarios.
Paper and Electronic Formats
While the UB-04 form is available in paper format, the vast majority of claims today are submitted electronically using the 837I transaction set, which mirrors the UB-04 field structure but complies with HIPAA electronic data interchange (EDI) standards. Regardless of submission method, every field on the form must be filled out with precise codes and data—including diagnosis codes (ICD-10-CM), revenue codes, HCPCS or CPT codes, NPI numbers, and payer details. The structure of the UB-04 supports efficient automated claims processing, which is critical to revenue cycle management (RCM).
Core Purpose of the UB-04 Form
- Submit claims for hospital and facility-based services to Medicare, Medicaid, and private payers
- Capture institutional data elements, such as patient status, admission type, and discharge disposition
- Align facility claims with coding standards, payer-specific rules, and federal billing regulations
- Enable the uniformity needed for national reimbursement systems like DRG and APC
- Document a wide range of services—from room and board charges to diagnostic imaging and surgical care
Why the UB-04 Matters in Medical Billing
A single claim error on the UB-04 can delay payment by weeks—or lead to a denial altogether. That’s why institutional providers rely on accurate completion and deep knowledge of how this form interacts with revenue codes, diagnosis coding, and payer contracts. When completed correctly, it supports:
- Faster reimbursements
- Fewer denials and rejections
- Improved claim audit results
- Compliance with payer policy and CMS rules
Providers and Facilities That Use the UB-04
The UB-04 form in medical billing is not a one-size-fits-all tool—it is purpose-built for institutional healthcare providers that render services in facilities rather than in office settings. Unlike the CMS form used by physicians and private practitioners, the UB-04 supports the complex billing needs of healthcare institutions that deliver coordinated, multi-department services over multiple days or episodes of care.
Common Providers That Use the UB-04 Form
1. Acute Care Hospitals
- Used for both inpatient and outpatient services
- Bill for room and board, surgery, ICU, labs, diagnostics, and emergency department services
- DRG-based reimbursement under Medicare
2. Skilled Nursing Facilities (SNFs)
- Submit claims for long-term care or post-acute rehab stays
- Include therapies (PT/OT/ST), nursing care, medications, and room charges
- Must comply with Medicare Part A SNF Consolidated Billing (CB) requirements
3. Inpatient Rehabilitation Facilities (IRFs)
- Use UB-04 to bill for intensive rehabilitation programs such as stroke, spinal cord injury, or post-surgical therapy
- Captures functional status codes, physician visits, nursing services, therapy hours
4. Psychiatric and Behavioral Health Hospitals
- Bill for psychiatric admissions, crisis stabilization, and behavioral therapy sessions
- Requires precise documentation for diagnosis, length of stay, and discharge planning
5. Long-Term Care Hospitals (LTCHs)
- Serve patients requiring extended hospital-level care (typically >25 days)
- Complex claims include ventilator use, infection control, wound care, and respiratory therapy
6. Hospice Care Providers
- UB-04 is used to bill for Medicare-certified hospice services
- Includes home visits, inpatient respite care, and palliative medications
7. Home Health Agencies (HHAs)
- Submit claims via UB-04 under Medicare Part A and Medicaid
- Use HIPPS codes, visit type, frequency, and OASIS assessments
8. Federally Qualified Health Centers (FQHCs) and Rural Health Clinics (RHCs)
- When billing for institutional-type services (e.g., in-clinic infusions or behavioral therapy), UB-04 is used
- Special payment structures apply (e.g., encounter-based)
9. Ambulatory Surgery Centers (ASCs) (when part of a hospital system)
- If owned and operated by hospitals, ASCs may use UB-04 for outpatient surgery claims
Summary of Facility Types Using UB-04
| Facility Type | Billing via UB-04? | Notes |
|---|---|---|
| Acute Care Hospital | ✅ Yes | Inpatient & outpatient billing |
| Skilled Nursing Facility (SNF) | ✅ Yes | Part A and Part B Medicare services |
| Inpatient Rehab Facility (IRF) | ✅ Yes | Rehabilitation-focused services |
| Home Health Agency (HHA) | ✅ Yes | OASIS-based claims, home visits |
| Hospice Care Provider | ✅ Yes | Palliative services under Medicare hospice benefit |
| Long-Term Care Hospital (LTCH) | ✅ Yes | Ventilation, extended inpatient services |
| Behavioral Health Hospital | ✅ Yes | Mental health admissions and therapy billing |
| Ambulatory Surgery Center (Hospital) | ✅ Sometimes | Only if part of hospital system |
| Private Practice / Physician Clinic | ❌ No | CMS-1500 is used |
Detailed Field-by-Field Explanation of UB-04 (Form Locator Boxes 1–81)
To accurately complete the UB-04 form while billing for facilities, billers must understand the meaning and usage of each Form Locator (FL)—the numbered fields that capture all required data for institutional claims. There are 81 Form Locators on the UB-04, though not all are used in every claim. Below is a breakdown of the most critical fields, grouped by category, with explanations and tips.
Provider & Facility Information (FL 1–8)
| Form Locator | Description | Example / Notes |
|---|---|---|
| FL 1 | Provider Name, Address | Legal name of hospital or facility |
| FL 2 | Pay-to Name, Address | Where payments should be sent (optional in many cases) |
| FL 3a / 3b | Patient Control Number / Medical Record # | Unique ID for internal tracking |
| FL 4 | Type of Bill | 3-digit code: Facility type + bill classification + frequency |
| FL 5 | Federal Tax Number | EIN used for tax and payer identification |
| FL 6 | Statement Covers Period | Service start and end date (e.g., admission to discharge) |
| FL 7 | Reserved for Assignment by CMS | Leave blank unless instructed by payer |
| FL 8a–8b | Patient ID and Birth Date | Demographics for patient identification |
Patient & Subscriber Information (FL 9–17)
| FL | Description | Example / Notes |
|---|---|---|
| FL 9 | Patient Address | Full street address, city, state, and ZIP code |
| FL 10 | Patient’s Sex | M / F / U (unknown) |
| FL 11–12 | Admission Date and Hour | Especially important for inpatient or ER billing |
| FL 13 | Admission Type | Urgent, elective, trauma, etc. |
| FL 14 | Admission Source | Physician referral, transfer from another facility |
| FL 15 | Point of Origin for Admission | Required for some inpatient and outpatient billing |
| FL 16 | Discharge Hour | 24-hour time format |
| FL 17 | Discharge Status | Indicates where the patient went after discharge |
Payer Information & Insurance Details (FL 50–65)
| FL | Description | Example / Notes |
|---|---|---|
| FL 50 | Payer Name | Medicare, Medicaid, BCBS, etc. |
| FL 51 | Health Plan ID | Usually optional |
| FL 52 | Release of Information Indicator | Y/N |
| FL 53 | Assignment of Benefits Indicator | Y/N |
| FL 54 | Prior Payments | Amounts paid by other insurers |
| FL 55 | Estimated Responsibility | Patient’s estimated financial portion |
| FL 56 | National Provider Identifier (NPI) | Billing provider’s NPI |
| FL 58–60 | Insured Name, ID, Group Number | Payer-specific details |
| FL 61–65 | Employer, Plan Name, Release Info | As required by insurer |
Revenue & Procedure Coding (FL 42–49)
| FL | Description | Notes |
|---|---|---|
| FL 42 | Revenue Code | 4-digit codes identifying type of service (e.g., 0300 = Lab) |
| FL 43 | Revenue Description | Short label for service (e.g., Blood Test) |
| FL 44 | HCPCS/Rates | CPT/HCPCS codes for outpatient claims |
| FL 45 | Service Date | Date of individual service rendered |
| FL 46 | Units of Service | Number of units billed |
| FL 47 | Total Charges | Total charges per revenue code line |
| FL 48 | Non-covered Charges | Amount not covered by payer |
| FL 49 | Reserved for Future Use | Typically left blank |
Diagnosis & Procedure Codes (FL 67–74)
| FL | Description | Notes |
|---|---|---|
| FL 67 | Principal Diagnosis Code | ICD-10-CM code primarily responsible for services |
| FL 67A–Q | Other Diagnosis Codes | Additional conditions affecting care |
| FL 69 | Admitting Diagnosis | Condition as diagnosed at time of admission |
| FL 70A–C | Patient’s Reason for Visit Codes | Often used in outpatient billing |
| FL 71 | Prospective Payment System (PPS) Code | DRG/APC codes for Medicare reimbursement |
| FL 72 | External Cause of Injury Codes | ICD-10-CM external cause codes (e.g., fall, MVA) |
| FL 74 | Principal Procedure Code & Date | For inpatient surgical/medical procedures |
Attending and Referring Provider Data (FL 76–79)
| FL | Description | Example / Notes |
|---|---|---|
| FL 76 | Attending Provider NPI | Required for all claims |
| FL 77 | Operating Physician NPI | For surgical or interventional procedures |
| FL 78 | Other Provider | Consulting or referring physician |
| FL 79 | Additional Physician | Optional depending on claim complexity |
Special Codes and Miscellaneous (FL 18–41, FL 80–81)
| FL | Description | Notes |
|---|---|---|
| FL 18–28 | Condition Codes | Define special conditions (e.g., hospice, accident involvement) |
| FL 29–34 | Accident/Injury Dates | Auto, work, or liability injury information |
| FL 35–36 | Occurrence Codes and Dates | Key events affecting billing (e.g., onset of symptoms) |
| FL 39–41 | Value Codes and Amounts | Medicare-specific financial details (e.g., deductible amounts) |
| FL 80 | Remarks | Free-text for payer instructions or documentation |
| FL 81 | Taxonomy Codes and Additional Info | Used for legacy codes or billing-specific details |
Key Elements Unique to the UB-04 Form
Key Fields That Define the UB-04 Form
While most healthcare billing forms collect patient and provider details, the UB-04 includes specialized fields that classify institutional services with much finer granularity. These fields are crucial to payer reimbursement and often misunderstood by general billers.
1. Type of Bill (FL 4)
A 3-digit code that summarizes:
- Facility type (e.g., hospital, SNF)
- Bill classification (e.g., inpatient, outpatient)
- Frequency (e.g., original, corrected, voided)
Format: XXX → 1st digit = facility, 2nd = care type, 3rd = bill frequency
Example:111 = Hospital, Inpatient, Original Claim331 = SNF, Inpatient, Original Claim
> Used by payers to route the claim to the correct adjudication process.
2. Revenue Codes (FL 42)
- A 4-digit numeric code used to categorize services rendered.
- Each revenue code corresponds to a cost center within the facility.
| Revenue Code | Description |
|---|---|
| 0100 | Room and Board |
| 0250 | Pharmacy |
| 0300 | Laboratory Services |
| 0420 | Physical Therapy |
| 0450 | Emergency Room |
Revenue codes are essential for Medicare and Medicaid payment grouping systems like DRG, APC, or per diem.
3. Occurrence Codes and Dates (FL 31–34)
- Used to report significant events or dates that impact the billing or eligibility.
- Tied to coverage start/stop, accident dates, or qualifying periods.
Examples:
- 11 = Date of onset of symptoms
- 50 = Date beneficiary became eligible for Medicaid
4. Condition Codes (FL 18–28)
Two-character alphanumeric codes used to explain unusual billing conditions or circumstances.
| Code | Meaning |
|---|---|
| 04 | Information only bill (no payment requested) |
| 20 | Beneficiary requested billing |
| 44 | Inpatient admission changed to outpatient |
Helps flag claims for special payer processing rules.
5. Discharge Status Code (FL 17 or FL 6X range)
- Indicates the patient’s disposition at the end of service.
- Used in DRG payment systems to determine reimbursement accuracy.
| Code | Status Description |
|---|---|
| 01 | Discharged to home |
| 02 | Discharged to another facility |
| 20 | Expired |
Critical for Medicare post-acute care payment calculations.
6. Value Codes (FL 39–41)
These codes communicate monetary amounts related to benefits, deductibles, or benefit days used.
| Code | Status Description |
|---|---|
| 01 | Most recent semi private room rate |
| 12 | Working Aged beneficiary/spouse with employer group health plan |
| 80 | Covered days |
7. Form Locator 81 – Additional Codes
Used for reporting:
- Taxonomy codes
- Legacy provider IDs
- Condition-specific identifiers (e.g., trauma registry numbers)
May also be used for payer-specific overrides or edits.
Most Common UB-04 Errors (and How to Prevent Them)
Even experienced billers can make mistakes when completing the UB-04 (CMS-1450) form. Since institutional billing claims go through stringent edits (especially by Medicare, Medicaid, and commercial payers), even a minor inconsistency can lead to denials or delays. Here are the most frequent UB-04 errors—along with clear tips to avoid them:
1. Incorrect or Missing Type of Bill Code (FL 4)
- Error: Using the wrong bill type (e.g., outpatient instead of inpatient)
- Impact: Claim processed incorrectly or rejected entirely
- Fix: Always confirm the 3-digit TOB code against payer policy for the service type and visit frequency.
2. Mismatched Revenue Codes and HCPCS (FL 42 & 44)
- Error: Using a revenue code that doesn’t align with the HCPCS/CPT
- Impact: Suspended claims, underpayment, or denial
- Fix: Refer to payer-specific revenue code-HCPCS crosswalks (especially Medicare’s).
3. Missing or Invalid Diagnosis Code (FL 67)
- Error: Invalid ICD-10-CM code, or truncated diagnosis entries
- Impact: DRG grouping failure, medical necessity denial
- Fix: Use updated ICD-10 codes and validate with coding software or CCI edits before submission.
4. Incorrect Discharge Status (FL 17 or FL 6X Range)
- Error: Reporting “01” (discharged home) when patient was transferred
- Impact: DRG payment error or audit risk
- Fix: Ensure the discharge disposition matches patient record and post-acute care plan.
5. Omitted Value, Condition, or Occurrence Codes
- Error: Leaving FL 18–41 blank when they apply (e.g., accident, hospice care)
- Impact: Payment delay or rejection due to incomplete claim data
- Fix: Review payer billing instructions for codes based on care setting and reason for service.
6. Provider NPI or Taxonomy Code Errors (FL 56, 81)
- Error: Submitting an invalid or outdated NPI, or missing taxonomy in FL 81
- Impact: Payer can’t identify the provider; claim rejected
- Fix: Always cross-check provider NPI against the NPPES registry and taxonomy code lists.
7. Improper Use of Occurrence Dates
- Error: Reporting an incorrect accident or onset date
- Impact: Denied due to untimely filing or incorrect benefit coordination
- Fix: Match occurrence codes and dates with clinical documentation (e.g., progress notes, H&P).
8. Using Facility NPI in the Rendering Provider Field
- Error: Substituting the facility’s NPI for the attending/operating provider
- Impact: Rejection due to missing attending provider requirement
- Fix: Input individual NPI of the attending/operating provider in FL 76–79.
9. Inconsistent Dates of Service Across Fields
- Error: FL 6 (Statement Period) doesn’t match revenue line dates in FL 45
- Impact: Suspicion of incorrect billing, audit flag
- Fix: Reconcile Statement Covers Period with individual Service Dates.
10. Incorrect Payer Order (Primary vs. Secondary)
- Error: Listing Medicare as secondary when it should be primary (or vice versa)
- Impact: Coordination of benefits (COB) rejections
- Fix: Follow COB rules and complete FL 50–65 accurately.
Pro Tips to Minimize UB-04 Errors
- Use billing scrubbers or RCM tools with UB-04 edit validation
- Train staff on payer-specific UB-04 rules
- Monitor remittance advice (RA) for denial trends
- Keep coding manuals and NUBC updates current
UB-04 vs. CMS-1500 – Key Differences in Billing Forms
Many providers and billing teams often remain confused between the two billing forms. While both are used to submit claims for medical services, they differ in purpose, structure, and usage
| Criteria | UB-04 (CMS-1450) | CMS-1500 (HCFA) |
|---|---|---|
| Form Used For | Institutional billing (hospitals, SNFs, hospices) | Professional billing (physicians, clinics, labs) |
| Maintained By | National Uniform Billing Committee (NUBC) | National Uniform Claim Committee (NUCC) |
| Claim Type | Facility-based claims | Individual or group provider claims |
| Fields Included | 81 Form Locators: revenue codes, condition codes, etc. | 33 Fields: NPI, diagnosis, CPT/HCPCS, etc. |
| Billing Method | UB-04 or 837I (electronic) | CMS-1500 or 837P (electronic) |
| Typical Payers | Medicare Part A, Medicaid, Commercial plans (facility claims) | Medicare Part B, Medicaid, Commercial plans (provider claims) |
| Format | Red-ink scannable form with 81 FLs | Red-ink form with 33 fields |
UB-04 Billing Guidelines by Payer (Medicare, Medicaid, and Commercial)
Payer-Specific UB-04 Billing Rules & Guidelines
Though the UB-04 is a universal form, each payer (Medicare, Medicaid, private insurers) has distinct policies that affect:
- Which fields are mandatory
- Acceptable coding formats
- Required attachments or documentation
- Timeframes for filing
Below is a breakdown of payer-specific UB-04 requirements:
1. Medicare (UB-04 for Medicare Part A)
Form version: CMS-1450 / 837I
Submission methods: Paper or electronic via EDI
Payer ID: Varies by MAC (Medicare Administrative Contractor)
Key UB-04 requirements:
- Type of Bill (TOB): Must match care setting (e.g., 111 for inpatient)
- FL 42 (Revenue Codes): Required for grouping under DRGs/APCs
- FL 67 (Diagnosis Codes): Must use ICD-10-CM format
- FL 76–79: NPI of attending and operating physicians
- Condition Codes: Use CC 04 for informational-only claims
- Occurrence Codes: Required for hospice and accident reporting
Use CMS’s Medicare Claims Processing Manual for UB-04 guidance by care type.
2. Medicaid
State-specific rules: Each state Medicaid program customizes UB-04 rules
Common requirements:
- Enrollment-specific Payer ID and taxonomy codes in FL 81
- Revenue Codes often mapped differently than Medicare
- Condition and Occurrence Codes used more extensively (e.g., CC 30 for hospice)
- Attachments: Consent forms or authorizations may be required
- Timely Filing Limits: 90–365 days depending on state.
Always verify with your state’s Medicaid provider manual.
3. Commercial Insurance Payers (Aetna, Cigna, BCBS, UHC, etc.)
Varied rules across carriers: Refer to provider portals or EDI companion guides
General requirements:
- FL 50–65: COB (Coordination of Benefits) section must be complete
- Prior Authorization Numbers: Often required in FL 63
- Accurate Discharge Status: Commercial plans flag errors in FL 17 or FL 6X
- Paper Claims: UB-04 form must be printed in red ink on CMS-1450 standard stock
- Attachments/Notes: Can be submitted via payer portals (or in FL 80)
Avoid blanket submissions. Tailor your claim formatting per payer-specific UB-04 edits
4. Secondary Payers (Coordination of Benefits)
If Medicare or a commercial plan is secondary, submit with:
- FL 54 (Prior Payments)
- FL 60 (Insured’s ID number)
- EOB from the primary payer (if required)
5. Timely Filing by Payer (General Guidelines)
| Payer | Time Limit to File |
|---|---|
| Medicare | Within 1 calendar year of DOS |
| Medicaid | Varies by state (90–365 days) |
| Aetna / Cigna | Typically 90–180 days |
| UHC / BCBS | 180 days or per contract |
Best Practices for Payer-Specific UB-04 Success
✔️ Use payer edit rules in your EHR or billing system
✔️ Keep a UB-04 payer matrix or checklist per carrier
✔️ Run trial claims for high-dollar inpatient admissions
✔️ Monitor RAs/ERAs for payer-specific denial trends
✔️ Stay current with payer newsletters and policy bulletins
UB-04 in Electronic Claim Submission (837I File Format)
What is the 837I Format?
The 837I is the Electronic Data Interchange (EDI) version of the UB-04 form. While UB-04 is the paper format, 837I is the electronic equivalent, used to submit institutional claims digitally to:
- Medicare
- Medicaid
- Commercial payers
- Clearinghouses
“I” stands for Institutional — distinguishing it from 837P (Professional) and 837D (Dental) formats.
UB-04 vs. 837I: What’s the Difference?
| Feature | UB-04 (CMS-1450) | 837I EDI File |
|---|---|---|
| Format | Paper or PDF | Electronic data format (X12 – 005010X223A2) |
| Submission Method | Manual or fax/mail | Through clearinghouses or direct EDI |
| Standard Use | Institutional claim billing | Institutional claim billing (automated) |
| Governing Body | NUBC | CMS and X12N (HIPAA compliant) |
Key Elements of the 837I EDI File
The 837I format contains segments that mirror UB-04 fields. These include:
| UB-04 Field | 837I Segment | Purpose |
|---|---|---|
| FL 1 (Billing Provider Info) | NM1, N3, N4, REF | Identifies billing entity & address |
| FL 4 (Type of Bill) | CLM05-1 | Facility and frequency code |
| FL 42–47 (Revenue Lines) | SV2 | Revenue code, HCPCS, charges |
| FL 67 (Diagnosis Codes) | HI segment | Principal and secondary ICD-10 codes |
| FL 76–79 (Provider IDs) | NM1, PRV, REF segments | Attending, operating, rendering providers |
| FL 50–65 (Payer Info) | SBR, NM1, N3, REF | Subscriber, payer, and insured info |
EDI files require adherence to ASC X12N 837I Implementation Guide, which includes loop, segment, and element requirements.
How to Submit an 837I Claim
1.Prepare the claim data
Export the UB-04 equivalent data from your EHR or billing software.
2.Map the data to the 837I format
Use middleware or clearinghouse tools to convert it to EDI format.
3.Validate the file
Run the claim through:
- HIPAA validation
- Payer-specific edits (CIC, NCCI)
4.Submit to a clearinghouse or payer directly
Use secure FTP or direct connections (EDI Gateway).
5.Check for 999 and 277CA responses
These are acknowledgments from the payer for claim receipt and errors.
Benefits of Electronic UB-04 (837I)
- Faster reimbursement cycles
- Improved claim tracking & audit trails
- Fewer manual errors and rejections
- HIPAA-compliant and secure
- Supports bulk institutional billing (batch claims)
Tools that Support 837I
- Clearinghouses: Availity, Change Healthcare, Office Ally
- RCM Software: Kareo, AdvancedMD, eClinicalWorks
- EDI Gateways: Ability Network, Optum, Trizetto
Frequently Asked Questions
What is the UB-04 form used for in medical billing?
UB-04, also called CMS-1450, is used to bill institutional claims for services like hospital, SNF, and hospice care under Medicare Part A and other insurers.
Who uses the UB-04 form?
Hospitals, rehab centers, hospices, and nursing homes use the UB-04 to bill facility-based services.
What are revenue codes on the UB-04?
Revenue codes indicate the type of service or department (e.g., ER, lab) and are essential for payer reimbursement.
What is a Type of Bill (TOB) on the UB-04?
The Type of Bill (TOB) is a 3-digit code that identifies the facility type and billing frequency.
Can I submit a UB-04 electronically?
Yes, UB-04 claims can be submitted electronically using the 837I EDI format through clearinghouses or direct payer connections.
What is the difference between UB-04 and 837I?
UB-04 is the paper form; 837I is its electronic EDI equivalent used for submitting institutional claims digitally.
What are common errors on the UB-04 form?
Common UB-04 errors include wrong revenue codes, invalid diagnosis, incorrect TOB, and missing provider or occurrence codes.
What is Form Locator 67 on the UB-04?
Form Locator 67 contains the principal diagnosis code, which drives reimbursement under DRGs for inpatient claims.
How many fields does the UB-04 form have?
The UB-04 form has 81 Form Locators used to capture patient, provider, service, and billing details.
How is DRG reimbursement linked to the UB-04 form?
Hospitals use UB-04 to report diagnoses and procedures, which group into Diagnosis Related Groups (DRGs). Accurate coding on Form Locators ensures correct Medicare Part A reimbursement.
What are occurrence codes on the UB-04 form?
Occurrence codes capture specific events like accident dates, onset of symptoms, or qualifying stays. Incorrect or missing codes often trigger payer denials or delays.
How do condition codes work on the UB-04?
Condition codes indicate special circumstances, such as billing for hospice, Medicare secondary payer, or outpatient services. They guide payer processing and coverage decisions.
What are value codes on the UB-04?
Value codes report additional payer-relevant amounts, such as patient liability, Medicare deductible, or blood units furnished. Incorrect reporting can cause underpayments.
How does the UB-04 support Medicare crossover claims?
When Medicare pays primary, UB-04 enables automatic crossover of remaining balances to Medicaid or secondary payers. Missing fields can block crossover and delay reimbursement.
What role does UB-04 play in outpatient facility billing?
Though widely used for inpatient, UB-04 is also required for outpatient services at hospitals, SNFs, and rehab centers. Correct revenue and TOB codes ensure payment.
Why do payers reject UB-04 claims for invalid NPI or taxonomy?
Claims require the billing provider’s correct NPI, taxonomy, and facility type. Mismatches between provider enrollment and UB-04 entries often trigger payer rejections.
How does UB-04 interact with Medicare Part A vs Part B?
Part A institutional services (hospital, SNF, hospice) bill via UB-04, while Part B professional services use CMS-1500. Facilities often submit both, depending on service.
What happens if revenue codes don’t match CPT/HCPCS codes on UB-04?
Mismatch between revenue codes and procedure codes is a top denial reason. Payers expect alignment to validate the type and location of service.
Are UB-04 forms required for Medicaid billing?
Yes. Most state Medicaid programs mandate UB-04 for institutional claims. Requirements vary by state, especially for behavioral health and long-term care facilities.
Can UB-04 claims be submitted electronically?
Yes. Most clearinghouses and payers accept UB-04 data electronically in the 837I format, even though paper UB-04 is still widely referenced.
Do all insurance companies accept the UB-04 form?
Yes, but requirements for fields like value codes, condition codes, and revenue codes vary by payer.
