The Internal ID (formerly called Provider Activity ID) is a unique code or identifier that your organization creates. It is used in combination with the data in the fields activity type, and activity date to uniquely identify your activity records. Providers should not use their assigned seven-digit provider ID number as an Internal ID, since this number would be the same for all activities you provide. 

The Internal ID field is optional, except in the following cases:

–When your organization offers multiple activities in the same format on the same date

–When entering activities via batch upload or web services

–When the activity offers MOC