Diagnosis Codes on the UB-04

Key points

Use the diagnosis information produced by the facility's documentation and coding process.
Institutional claims can use principal and other diagnosis positions.
Review diagnoses alongside bill type, dates, procedures, revenue lines, and the documented encounter.

Start with the coded record

Use the diagnosis information produced by the facility's documentation and coding process. The UB-04 is the reporting vehicle, not the place to decide which undocumented diagnoses might improve payment.

Sequence matters

Institutional claims can use principal and other diagnosis positions. Reordering codes during data entry can change the meaning of the claim.

Check diagnosis relationships

Review diagnoses alongside bill type, dates, procedures, revenue lines, and the documented encounter. A correct code can still be wrong for the episode being billed.

Institutional-claim review

Use the current coded clinical record as the source for diagnoses.
Review principal/other diagnosis sequencing and payer rules for the claim type.
Recheck diagnoses after any change to the patient stay, services, or coding review.

Diagnosis sequencing is part of the institutional claim story

Institutional claims can distinguish a principal diagnosis from additional diagnoses, and payer processing can depend on sequencing and the claim type. Coding staff should work from the current clinical record and applicable ICD-10-CM guidance. Billing staff should then verify that the coded diagnoses transferred correctly to the UB-04 data and were not truncated, reordered, or carried forward from another encounter.

Sources and verification

Use the CMS institutional-claim sources below for current CMS-1450/UB-04 guidance, then apply the payer’s rules for the facility claim.

Related guides

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