What are Occurrence Codes used for on UB-04?

• A. They identify events affecting payment.
• B. They specify patient diagnoses.
• C. They list CPT procedure codes.
• D. They determine the billing provider.

Answer: (A)

Occurrence Codes on UB-04 identify events during a patient’s stay that can influence how the claim is paid. They flag dates or happenings—such as admission, discharge, transfer, or other time-based events—that provide the payer with context for payment processing. These codes often work with Occurrence Span Codes to show exact dates or date ranges, helping determine factors like coverage, timing of services, or potential adjustments.

They aren’t used to specify patient diagnoses (that’s the ICD-10-CM codes) or to list the procedures performed (that’s the CPT/HCPCS codes). They also don’t determine who the billing provider is—the provider arrangement and payer rules set that. So the purpose of occurrence codes is to mark events that can affect how the claim is evaluated and paid.