The “Patient’s Account No.” is the identifier assigned by the provider.

NUCC INSTRUCTIONS: Enter the patient’s account number assigned by the provider of service’s or supplier’s accounting system.

Do not enter hyphens with numbers. Enter numbers left justified in the field.

Note: While the patient’s account number is a required data element in the 837P claim transaction, it is strongly encouraged but not required on a paper claim. Payers or their vendors may choose to enter a default into the field if no number is reported by the provider for reporting in the 835 remittance. If no default number is used within the internal processing system, payers would report a single zero on an 835 remittance per the 835 TR3.

MEDICARE INSTRUCTIONS: Enter the patient's account number assigned by the provider's of service or supplier's accounting system. This field is optional to assist the provider in patient identification. As a service, any account numbers entered here will be returned to the provider.