How are ICD-10-CM diagnoses reported on UB-04?

• A. Only as narrative description without links.
• B. In a separate file attached to the claim.
• C. As principal and secondary diagnoses on the claim, linked to lines via diagnosis pointers.
• D. As CPT codes.

Answer: (C)

On a UB-04, ICD-10-CM diagnoses are reported as the principal diagnosis (the main reason for the admission) and any secondary diagnoses, with diagnosis pointers that link each code to the corresponding service lines. This linkage is essential for accurate medical necessity and proper claim processing because it shows exactly which diagnosis supports each line item. Diagnoses are not reported as CPT codes, nor simply as a narrative description or in a separate file—the structured approach with pointers is the standard the claim form requires.