Data Element Name: Insurance Number states blanks are not allowed. Please submit blank ("") for Insurance Number if Data Element Name: Payer = "A" (i.e. Self-Pay) or no insurance number is known. Insurance Number is required if element Payer is Medicare ("C"), Medicaid ("D"), Commercial Insurance ("F"), or Blue Cross ("G").
This will be reflected in version 1.21 of the dictionary, and is considered official for submission of Q2 2014 cases (data submission beginning August 1, 2014).