Convert HIPAA 837I Claims to UB-04 (CMS-1450)

The UB-04 (CMS-1450) is the standard claim form for hospitals and institutional providers. The HIPAA 837I is its electronic equivalent. With 81 form locators, 22 revenue lines per page, and support for three payers on a single form, the UB-04 is significantly more complex than the CMS-1500. This article provides the field-by-field mapping from 837I segments to UB-04 form locators, based on production-tested conversion logic.

In this article:

Understanding the Two Formats
Provider Information (FL 1–7)
Patient Information (FL 8–11)
Condition and Admission (FL 12–30)
Revenue Lines (FL 42–49)
Payer Information (FL 50–65)
Diagnosis and Procedure (FL 66–74)
Key Differences from CMS-1500

Convert an 837 Claim to PDF

Understanding the Two Formats

The mapping examples in this article show how 837I data corresponds to the UB-04 under the CMS and NUBC instructions. They are reference mappings for readers, not a record of any one map’s output.

The UB-04 form uses numbered Form Locators (FLs) organized into sections:

FL 1–11: Provider and patient identification
FL 12–23: Condition codes, occurrence codes, value codes
FL 24–30: Revenue code lines (up to 22 lines per page)
FL 31–37: Occurrence and condition spans
FL 38–41: Responsible party information
FL 42–49: Revenue codes, descriptions, charges, and service dates
FL 50–65: Payer information (primary, secondary, tertiary)
FL 66–81: Diagnosis, procedure, and provider information

The 837I organizes data into hierarchical loops:

2000A (Billing Provider) — the hospital or facility
2000B (Subscriber) — the insured person
2000C (Patient) — if different from subscriber
2300 (Claim) — institutional claim data
2400 (Service Line) — revenue code lines

Provider Information (FL 1–7)

FL 1: Billing Provider Name, Address, Phone

From the Billing Provider loop (2010AA), NM1 entity code “85”:

NM1*85*2*GENERAL HOSPITAL****XX*1234567890~
N3*100 HOSPITAL DR*WING B~
N4*ANYTOWN*NV*89101~
PER*IC**TE*5551234567~

FL 1 line 1: Provider name (NM103)
FL 1 line 2: Street address (N301 + N302)
FL 1 line 3: City, State ZIP (N401 + N402 + N403)
FL 1 phone: From PER segment (qualifier “TE”)

FL 3a: Patient Control Number

CLM*PATIENT_ACCT_123*15000***11:A:1~
    ^^^^^^^^^^^^^^^^
    FL 3a = CLM01

FL 4: Type of Bill

A 4-character code constructed from CLM05:

CLM*ACCT123*15000***11:A:1~
                     ^^ ^ ^
                     |  | +-- FL 4 digit 4: Frequency (1=Admit/Discharge)
                     |  +---- FL 4 digit 3: (not used in 837)
                     +------- FL 4 digits 1-2: Facility type + billing class

Common type of bill codes: 0111 (Hospital Inpatient), 0131 (Hospital Outpatient), 0321 (Home Health).

FL 5: Federal Tax ID

REF*EI*123456789~
       ^^^^^^^^^
       FL 5 = REF02

FL 6: Statement Covers Period

DTP*434*RD8*20250101-20250105~
            ^^^^^^^^ ^^^^^^^^
            From     Through

Patient Information (FL 8–11)

FL 8a: Patient Identifier

NM1*IL*1*DOE*JOHN***MI*MEMBER_ID~
                        ^^^^^^^^^
                        FL 8a = NM109

FL 8b: Patient Name

FL 8b = NM103 + ", " + NM104 + " " + NM105

FL 10: Patient Birth Date

DMG*D8*19550315*M~
       ^^^^^^^^
       FL 10 = reformatted to MMDDYYYY

FL 11: Patient Sex

DMG*D8*19550315*M~
                ^
                FL 11 = M or F

Condition and Admission (FL 12–30)

FL 12–13: Admission Date and Hour

DTP*435*DT*2025011514~
           ^^^^^^^^^^
           Date + Hour

FL 14: Admission Type

CL1*3*1*01~
    ^
    FL 14 = CL101 (1=Emergency, 2=Urgent, 3=Elective, 4=Newborn)

FL 15: Admission Source

CL1*3*1*01~
      ^
      FL 15 = CL102 (1=Physician Referral, 2=Clinic, 4=Transfer, etc.)

FL 17: Patient Discharge Status

CL1*3*1*01~
        ^^
        FL 17 = CL103 (01=Home, 02=Short-term hospital, 03=SNF, etc.)

Revenue Lines (FL 42–49)

The UB-04 holds up to 22 revenue code lines per page (compared to 6 service lines on the CMS-1500). Each line maps to one 2400 loop in the 837I.

FL 42: Revenue Code

SV2*0250*HC:99283~
    ^^^^
    FL 42 = SV201 (Revenue Code)

Common revenue codes: 0120 (Room & Board Semi-Private), 0250 (Pharmacy), 0260 (IV Therapy), 0301 (Lab Chemistry), 0450 (Emergency Room).

FL 44: HCPCS/Rates

SV2*0250*HC:99283~
         ^^ ^^^^^
         |  HCPCS code
         Qualifier

FL 45: Service Date

DTP*472*D8*20250115~
           ^^^^^^^^
           FL 45 = Date of service for this revenue line

FL 46: Units of Service

SV2*0250*HC:99283*150.00*UN*1~
                          ^^
                          FL 46 = SV205 (units)

FL 47: Total Charges

SV2*0250*HC:99283*150.00~
                  ^^^^^^
                  FL 47 = SV203 (charges per revenue line)

The last line (FL 47, line 23) carries the total of all charges.

Payer Information (FL 50–65)

The UB-04 supports up to three payers (Primary, Secondary, Tertiary). The 837I uses SBR01 to indicate payer order.

FL 50A/B/C: Payer Name

NM1*PR*2*BLUE CROSS****PI*12345~
         ^^^^^^^^^^
         FL 50A = NM103 (primary payer)

FL 56: Billing Provider NPI

NM1*85*2*GENERAL HOSPITAL****XX*1234567890~
                                 ^^^^^^^^^^
                                 FL 56 = NM109

FL 58A/B/C: Insured’s Name

NM1*IL*1*DOE*JOHN***MI*MEMBER_ID~
         ^^^  ^^^^  ^^
         FL 58 = "DOE, JOHN M"

FL 59A/B/C: Patient’s Relationship to Insured

SBR02	FL 59
18	Self
01	Spouse
19	Child
Other	Other

Diagnosis and Procedure (FL 66–74)

FL 67: Principal Diagnosis Code

HI*ABK:S7290A~
       ^^^^^^
       FL 67 = Principal diagnosis

FL 67A–Q: Other Diagnosis Codes

Up to 17 additional diagnosis codes, in their own HI segment with qualifier ABF:

HI*ABK:S7290A~
HI*ABF:M7981*ABF:Z87891~
       ^^^^^^^^^ ^^^^^^^^^^
       FL 67A    FL 67B

FL 69: Admitting Diagnosis Code

HI*ABJ:R0789~
       ^^^^^
      FL 69 = Admitting diagnosis

FL 74: Principal and Other Procedure Codes

From HI segment with qualifiers BBR (principal) and BBQ (other):

HI*BBR:0SG00ZZ:D8:20250102~
       ^^^^^^^    ^^^^^^^^
       ICD-10-PCS Date

Provider Identification (FL 76–81)

FL 76: Attending Provider

From the Attending Provider loop (NM1 entity code “71”):

NM1*71*1*SMITH*ROBERT*J***XX*1234567890~
         ^^^^^  ^^^^^^  ^     ^^^^^^^^^^
         Name                 NPI

FL 77: Operating Provider

From NM1 entity code “72” — the surgeon for surgical claims.

Multi-Page Institutional Claims

Unlike the CMS-1500’s 6 lines, the UB-04 holds 22 revenue code lines per page. However, complex hospital stays can easily exceed this:

A 5-day inpatient stay might have 50+ revenue lines (room, pharmacy, lab, radiology, supplies, etc.)
The conversion engine handles pagination automatically
Header information (FL 1–11, FL 38, FL 50–65) repeats on every page
Line 23 on each page carries page subtotals; the final page carries grand totals

Key Differences from CMS-1500 Mapping

Aspect	CMS-1500 (837P)	UB-04 (837I)
Form fields	33 boxes	81 form locators
Lines per page	6 service lines	22 revenue lines
Procedure codes	CPT/HCPCS	Revenue codes + HCPCS
Provider types	Rendering + Referring	Attending + Operating + Other
Payer slots	1 (primary only)	3 (primary + secondary + tertiary)
Diagnosis limit	4 per claim	18 per claim
Procedure codes	Not on form	Up to 6 ICD-10-PCS codes

Try It Yourself

Redix provides a live API that converts 837I claims to UB-04 PDFs:

POST https://demo.redix.com/api/v2/claims-to-pdf
Content-Type: application/json
X-API-Key: demo-key-12345

{
  "x12_content": "ISA*00*...",
  "output_format": "ub04"
}

Two PDF output methods. Redix supports two PDF output methods through the corresponding map packages. Method 2 produces a claim-data-only PDF without the form artwork, designed for use with preprinted UB-04 forms. Method 1 includes the form artwork and claim data together for review, sharing and archiving. Contact Redix to discuss the map package and printing setup for your workflow. For converting and archiving claim files locally, see the Redix Claims-to-PDF Workbench.

Conclusion

The 837I-to-UB-04 mapping is significantly more complex than its professional (837P/CMS-1500) counterpart. The UB-04 carries more diagnosis codes, supports three payers on a single form, includes surgical procedure codes, and has 22 revenue lines per page instead of 6.

Redix has maintained these institutional claim mappings in production for over 15 years, processing 837I files for hospitals, health systems, and clearinghouses. The mappings in this article show the standard 837I-to-UB-04 correspondence under the CMS and NUBC instructions, as a reference.

Frequently Asked Questions

How do you convert an 837I to a UB-04 form?

An 837I-to-UB-04 conversion maps data from X12 hierarchical loops and segments to the 81 form locators on the UB-04 (CMS-1450) form. Provider information comes from the 2010AA loop, patient data from NM1/DMG segments, revenue lines from SV2 segments in the 2400 loop, and diagnosis/procedure codes from HI segments. The mapped data is rendered onto a UB-04 PDF template at precise coordinates.

What is the difference between UB-04 and CMS-1500?

The CMS-1500 handles professional claims (837P) with 33 boxes and 6 service lines per page. The UB-04 handles institutional claims (837I) with 81 form locators and 22 revenue lines per page. The UB-04 supports up to 3 payers, 18 diagnosis codes, and ICD-10-PCS procedure codes — significantly more complex than the CMS-1500.

How many revenue lines fit on a UB-04 form?

The UB-04 holds up to 22 revenue code lines per page. Complex hospital stays can easily exceed this — a 5-day inpatient stay might have 50+ revenue lines covering room, pharmacy, lab, radiology, and supplies. The conversion engine handles pagination automatically, with header information repeating on every page.