Blue Cross put a notice on their Website in Big Red Letters:
WE WILL NO LONGER ACCEPT UNSPECIFIED ICD-10 CODES AFTER
We have already been warned by commercial carriers that there will be no grace period for ICD-10. Blue Cross obviously has been honoring some of those codes in the early days, but your billing staff should know that these claims will be denied after December 1, 2015.
Unspecified codes will almost always require records to show that there was no other way to code the actual symptom or disease process. In these unusual instances, the provider documentation will be key to getting paid.