7.3 UB-04 / CMS-1450 (Institutional) Claim

Purpose of the UB-04

The UB-04, formally the CMS-1450, is the standard claim form for institutional providers — hospitals (inpatient and outpatient), skilled nursing facilities (SNFs), home health agencies, hospice, dialysis centers, and rural health clinics. It is maintained by the National Uniform Billing Committee (NUBC). The electronic equivalent is the 837I (I for institutional).

Unlike the CMS-1500's 33 boxes, the UB-04 has 81 numbered fields called Form Locators (FLs). Institutional claims also rely on coded data sets — type of bill, revenue codes, condition/occurrence/value codes — far more than the professional claim does.

FL 4: Type of Bill (TOB)

The Type of Bill is a coded value (commonly shown as four digits with a leading zero) where each digit position has a meaning:

Reading TOB ranges with "x" as the frequency placeholder:

So 0111 is a hospital inpatient admit-through-discharge claim, and 0137 is a hospital outpatient replacement claim that corrects a previously paid claim.

FL 42: Revenue Codes

Revenue codes in FL 42 classify every charge line by the department or type of service that produced it. Each revenue line pairs with a charge amount (FL 47) and, for outpatient claims, usually a CPT/HCPCS code (FL 44) and units (FL 46).

Worked example: An outpatient surgery claim lists revenue code 0360 (OR services) with the surgical CPT and units, 0250 (pharmacy) for medications, and 0300 (lab) for pathology. Each line carries its own charge; the 0001 line totals them. A common trap: outpatient revenue lines that require a HCPCS code (e.g., 0636 drugs) but are submitted without one are rejected.

Required Identifiers and Codes

Key institutional fields the CPB exam expects you to recognize: FL 1 (provider name/address), FL 6 (statement covers period), FL 56 (facility NPI), FL 67 (principal diagnosis, with present-on-admission indicator), FL 67A–Q (other diagnoses), FL 76 (attending provider NPI), and FL 74 (principal procedure with date for inpatient surgical claims).

Occurrence, Value, and Condition Codes

Institutional claims carry coded supplemental data the payer needs to adjudicate:

• Occurrence codes (FLs 31–34) report a dated event — accident date (01–06), onset of symptoms (11), or a benefit-period start.
• Occurrence span codes (FLs 35–36) report a date range, such as the qualifying 3-day inpatient stay (span code 70/74) that must precede covered SNF care.
• Value codes (FLs 39–41) report a code paired with a dollar amount or numeric value — value code 80 (covered days), 81 (non-covered days), or A2 (deductible).
• Condition codes (FLs 18–28) flag special circumstances — condition code 44 (inpatient changed to outpatient), W2 (duplicate of original bill).

CMS-1500 vs UB-04: Choosing the Right Form

The deciding factor is who is billing, not the patient's diagnosis. A physician who treats a patient inside a hospital still bills the CMS-1500/837P for the professional component; the hospital bills the UB-04/837I for the facility component (room, nursing, supplies, OR time). Many inpatient encounters therefore generate both a professional and an institutional claim.

Trap: an emergency-department visit produces an ED physician CMS-1500 claim and a hospital UB-04 facility claim — billing both on one form is incorrect.

Inpatient vs Outpatient Institutional Billing

Whether a UB-04 is inpatient or outpatient changes how it is coded and paid. Inpatient claims (TOB 011x) are grouped into a Medicare Severity Diagnosis-Related Group (MS-DRG) based on the principal diagnosis, procedures, and complications/comorbidities, then paid a fixed amount under the Inpatient Prospective Payment System (IPPS). The principal diagnosis (FL 67) and present-on-admission (POA) indicators directly affect the DRG.

Outpatient hospital claims (TOB 013x) are paid under the Outpatient Prospective Payment System (OPPS) using Ambulatory Payment Classifications (APCs) driven by HCPCS codes on each revenue line. A biller who confuses the two will report the wrong code set and units, producing rejections.

Putting the Institutional Claim Together

A correct UB-04 ties the Type of Bill (the right facility, classification, and frequency) to the revenue codes (the departments that generated charges), the diagnoses and procedures (with POA and dates), and the occurrence/value/condition codes (the dated events and dollar amounts the payer needs). Each revenue line must reconcile to a charge, and the total (revenue 0001) must match the sum. Because the form carries 81 Form Locators and far richer code sets than the CMS-1500, institutional billing rewards methodical, checklist-driven completion — exactly the structured reasoning the CPB exam rewards.