The UB1 segment carries the institutional-billing data elements that populate a UB-82 (HCFA-1450) claim form. It captures blood deductible accounting, covered and non-covered day counts, condition codes, value amounts, occurrence dates, and the form-locator overflow fields specific to the UB-82 paper claim. UB1 is the predecessor of the UB2 segment, which carries the later UB-92 form data, and the two share the same institutional-billing vocabulary.
Purpose
UB1 conveys the financial and stay-related details that a provider reports to a payer on a UB-82 claim. These elements describe how much of a stay is covered, how blood products were furnished and replaced, which condition and occurrence codes apply, and the value amounts and codes that justify reimbursement. UB1 is informational at the segment level; the standard marks its fields as optional and relies on UB-specific value, condition, and occurrence code sets rather than general HL7 tables.
Used in
UB1 (UB-82 form data) and UB2 (UB-92 form data) carry institutional-billing form information, while GP1 and GP2 carry grouping and reimbursement (DRG-based) data. UB1 appears in BAR (billing and account) messages and in ADT institutional-billing contexts, typically following the PID and PV1 segments that establish patient and visit context.
Field-by-field reference
Source: HAPI HL7v2 v2.5.1 javadocs (UB1.html). Length is shown as —; Required and Table # are taken from the HL7 v2.5.1 standard where well-established. Many UB1 fields use UB-specific value, condition, and occurrence codes that have no general HL7 table, so those Table # cells are left —.
| Seq | Name | Data Type | Length | Req | Repeat | Table # | Description |
|---|---|---|---|---|---|---|---|
| UB1-1 | Set ID - UB1 | si | — | O | — | — | Sequence number for this UB1 instance |
| UB1-2 | Blood Deductible (43) | nm | — | O | — | — | Blood deductible amount applied |
| UB1-3 | Blood Furnished-Pints Of (40) | nm | — | O | — | — | Pints of blood furnished to patient |
| UB1-4 | Blood Replaced-Pints (41) | nm | — | O | — | — | Pints of blood replaced by donors |
| UB1-5 | Blood Not Replaced-Pints (42) | nm | — | O | — | — | Pints of blood not replaced |
| UB1-6 | Co-Insurance Days (25) | nm | — | O | — | — | Number of co-insurance days in stay |
| UB1-7 | Condition Code (35-39) | is | — | O | Y | — | UB-82 condition codes describing the claim |
| UB1-8 | Covered Days (23) | nm | — | O | — | — | Number of covered days in stay |
| UB1-9 | Non Covered Days (24) | nm | — | O | — | — | Number of non-covered days in stay |
| UB1-10 | Value Amount & Code (46-49) | uvc | — | O | Y | — | Value codes and their dollar amounts |
| UB1-11 | Number Of Grace Days (90) | nm | — | O | — | — | Approved grace days beyond review period |
| UB1-12 | Special Program Indicator (44) | ce | — | O | — | — | Indicator for special billing program |
| UB1-13 | PSRO/UR Approval Indicator (87) | ce | — | O | — | — | Peer review or utilization approval indicator |
| UB1-14 | PSRO/UR Approved Stay-Fm (88) | dt | — | O | — | — | Start date of approved stay |
| UB1-15 | PSRO/UR Approved Stay-To (89) | dt | — | O | — | — | End date of approved stay |
| UB1-16 | Occurrence (28-32) | ocd | — | O | Y | — | Occurrence codes and associated dates |
| UB1-17 | Occurrence Span (33) | ce | — | O | — | — | Occurrence span code for the claim |
| UB1-18 | Occur Span Start Date (33) | dt | — | O | — | — | Start date of the occurrence span |
| UB1-19 | Occur Span End Date (33) | dt | — | O | — | — | End date of the occurrence span |
| UB1-20 | UB-82 Locator 2 | st | — | O | — | — | State-defined data for form locator 2 |
| UB1-21 | UB-82 Locator 9 | st | — | O | — | — | State-defined data for form locator 9 |
| UB1-22 | UB-82 Locator 27 | st | — | O | — | — | State-defined data for form locator 27 |
| UB1-23 | UB-82 Locator 45 | st | — | O | — | — | State-defined data for form locator 45 |
Most-used fields
- UB1-1 Set ID - UB1: identifies the instance when more than one UB1 appears; optional even when present.
- UB1-7 Condition Code (35-39): repeating UB-82 condition codes that qualify the claim for payer rules.
- UB1-8 Covered Days (23) and UB1-9 Non Covered Days (24): the split between payable and non-payable days in the stay.
- UB1-10 Value Amount & Code (46-49): repeating value codes paired with dollar amounts that drive reimbursement.
- UB1-16 Occurrence (28-32): repeating occurrence codes and dates that document significant events during the stay.
Version differences (2.3 to 2.8.2)
- UB1 originates in early HL7 v2 releases as the carrier of UB-82 (HCFA-1450) form data and is retained largely unchanged through v2.5.1 for backward compatibility.
- As the UB-82 paper form was superseded by the UB-92, the UB2 segment was introduced to carry the newer form locators; UB1 remained for legacy UB-82 reporting.
- Data-type refinements over the 2.3 to 2.8.2 range (for example the value-amount and occurrence composites) tightened component definitions without changing UB1 field order or intent.
- By the later 2.x releases UB1 is effectively legacy: institutional billing increasingly relies on UB2 and on the grouping/reimbursement segments GP1 and GP2. Confirm field availability against the specific version in use.
Common mistakes
- Treating Set ID UB1-1 as required. It is optional in the standard; do not reject a UB1 that omits it.
- Confusing UB1 (UB-82) with UB2 (UB-92). The two segments are not interchangeable and use different form-locator fields.
- Expecting general HL7 tables for the condition, value, and occurrence codes. UB1 uses UB-specific code sets, not normalized HL7 tables, for most fields.
- Sending day counts in the wrong field. Covered (UB1-8) and non-covered (UB1-9) days are distinct from co-insurance days (UB1-6).
- Collapsing repeating fields. UB1-7, UB1-10, and UB1-16 repeat; flattening them into a single value loses claim detail.
Examples
Minimal UB1 (covered and non-covered days only):
UB1|1||||||||30|5
Fully populated UB1:
UB1|1|0|2|2|0|4|A1~A2|30|5|46^1200.00~47^350.00|3|01^Special^L|A^Approved^L|20260601|20260605|28^20260601~32^20260603|71^^L|20260601|20260605|LOC2DATA|LOC9DATA|LOC27DATA|LOC45DATA
Annotated breakdown:
UB1|1|0|2|2|0|4|A1~A2|30|5|46^1200.00~47^350.00|...
| | | | | | | | | |
| | | | | | | | | +-> UB1-10 Value Amount & Code: code 46 = $1200.00, code 47 = $350.00
| | | | | | | | +----> UB1-9 Non Covered Days = 5
| | | | | | | +-------> UB1-8 Covered Days = 30
| | | | | | +-------------> UB1-7 Condition Codes = A1, A2 (repeating)
| | | | | +---------------> UB1-6 Co-Insurance Days = 4
| | | | +-----------------> UB1-5 Blood Not Replaced-Pints = 0
| | | +-------------------> UB1-4 Blood Replaced-Pints = 2
| | +---------------------> UB1-3 Blood Furnished-Pints = 2
| +-----------------------> UB1-2 Blood Deductible = 0
+--------------------------> UB1-1 Set ID - UB1 = 1
In-context excerpt inside a BAR^P01 (billing account) message, after PID and PV1:
MSH|^~&|REGISTRATION|MERCYGEN|BILLING|MERCYGEN|20260610113000||BAR^P01^BAR_P01|MSG10241|P|2.5.1
EVN|P01|20260610113000
PID|1||MRN884412^^^MERCYGEN^MR||DOE^JANE^Q||19710204|F
PV1|1|I|3WEST^312^A^MERCYGEN||||1023^WELBY^MARCUS|||MED||||A|||1023^WELBY^MARCUS|IP|ACC778901|||||||||||||||||||||||||20260601|20260605
UB1|1|0|2|2|0|4|A1~A2|30|5|46^1200.00~47^350.00|3|01^Special^L|A^Approved^L|20260601|20260605|28^20260601|71^^L|20260601|20260605
Second in-context excerpt (a shorter UB-82 report following PV1):
MSH|^~&|REGISTRATION|RIVEROAKS|BILLING|RIVEROAKS|20260609090000||BAR^P01^BAR_P01|MSG55012|P|2.5.1
EVN|P01|20260609090000
PID|1||MRN200337^^^RIVEROAKS^MR||SMITH^ROBERT^A||19640812|M
PV1|1|I|5EAST^501^B^RIVEROAKS||||2210^HOUSE^GREGORY|||SUR||||A|||2210^HOUSE^GREGORY|IP|ACC661204|||||||||||||||||||||||||20260520|20260528
UB1|1||||||B1|8|0|48^900.00|||||||||||
FHIR mapping
- Source: UB1.
- Target: Not mapped at the segment level.
- Notes: No segment-level ConceptMap is published in the v2-to-FHIR IG for UB1. Institutional-billing data maps conceptually to the FHIR Claim resource (UB-04/837I billing). Covered and non-covered days, value codes, and occurrence information align with Claim.supportingInfo and Claim.item financial elements rather than a single normalized field.
Engine considerations
- UB1 fields are optional; a conformant engine should accept a UB1 with only a few populated fields and not reject on missing Set ID.
- Preserve repetitions in UB1-7, UB1-10, and UB1-16. Use repetition-aware accessors so condition, value, and occurrence entries round-trip without loss.
- Validate value-amount composites (UVC) and occurrence composites (OCD) by component rather than as flat strings.
- Treat UB-specific condition, value, and occurrence codes as opaque code sets; do not force them through general HL7 table validation.
- Be explicit about UB1 versus UB2 routing, since both can appear in institutional-billing flows and use different form locators.
How Vorro parses and produces UB1
Vorro parses UB1 into a normalized institutional-billing model that keeps each repeating group intact: condition codes (UB1-7), value amount and code pairs (UB1-10), and occurrence code and date pairs (UB1-16) are read as lists, while scalar day counts and blood-accounting fields are typed numerically. When producing UB1, Vorro emits fields in standard sequence, populates only the elements present in the source claim, and leaves the UB-specific code values unaltered so downstream payers receive them in their primary form. Form-locator overflow fields (UB1-20 through UB1-23) are passed through as state-defined strings without normalization.
