Complete only if the patient is not the Primary Subscriber (i.e., "Self" not checked in Item 18). Enter if dentist's office assigns a unique number to identify the patient that is not the same as the Subscriber Identifier number assigned by the payer (e.g., Chart #).
This information is triggered by the Billing screen, Patient Relation to Ins 1 Holder field and comes from the Patient Information screen, Patient Information tab, Chart Number field.