Field 1a is the Insured's ID Number. This information identifies the insured to the payer.

NUCC INSTRUCTIONS: Enter the insured’s ID number as shown on insured’s ID card for the payer to which the claim is being submitted. If the patient has a unique Member Identification Number assigned by the payer, then enter that number in this field.

FOR TRICARE: Enter the DoD Benefits Number (DBN 11-digit number) from the back of the ID card.

FOR WORKERS COMPENSATION CLAIMS: Enter the appropriate identifier of the employee.

FOR OTHER PROPERTY AND CASUALTY CLAIMS: Enter the appropriate identifier of the insured person or entity.

MEDICARE INSTRUCTIONS - Enter the patient's Medicare Health Insurance Claim Number (HICN) whether Medicare is the primary or secondary payer. This is a required field.