The “Diagnosis Pointer” is the line letter from Item Number 21 that relates to the reason the service(s) was performed.
NUCC INSTRUCTIONS: In 24E, enter the diagnosis code reference letter (pointer) as shown in Item Number 21 to relate the date of service and the procedures performed to the primary diagnosis. When multiple services are performed, the primary reference letter for each service should be listed first, other applicable services should follow. The reference letter(s) should be A – L or multiple letters as applicable. ICD-10-CM or ICD-9-CM diagnosis codes must be entered in Item Number 21. Do not enter them in 24E.
MEDICARE INSTRUCTIONS: This is a required field. Enter the diagnosis code reference number or letter (as appropriate, per form version) as shown in item 21 to relate the date of service and the procedures performed to the primary diagnosis. Enter only one reference number/letter
per line item. When multiple services are performed, enter the primary reference number/letter for each service.
When using form version 08/05, this reference will be either a 1, or a 2, or a 3, or a 4.
When using form version 02/12, the reference to supply in 24E will be a letter from A-L. Otherwise, the instructions above apply.
If a situation arises where two or more diagnoses are required for a procedure code (e.g., pap smears), the provider shall reference only one of the diagnoses in item 21.