This variable is contained in the following files: Carrier (Fee-for-Service)
Short SAS Name
RFR_PRFL
SAS Name
CARR_CLM_RFRNG_PIN_NUM

The provider identification number (PIN) of the physician/supplier (assigned by the MAC) who referred the beneficiary to the physician who ordered these services.

Comments
: 

CMS identifies providers using the National Provider Identifier (NPI; effective May 1, 2007), which replaces legacy numbers (UPINs, PINs, etc.) on the standard HIPPA claim transactions.

Source: NCH