This file is used primarily as a National Laboratory Test (NLT) database upgrade source file. When new/additional NLT codes are released to the field, they are exported in this file. The installation software takes the entries from the LAB NLT/CPT CODES (#64.81) and adds them to the WKLD CODE (#64) file, then deletes that installed code from this file. If the installation is successful, this file will be empty. NORMALLY, THIS FILE HAS NO DATA EXCEPT DURING INITIAL STAGES OF DATABASE UPGRADE. The end user never uses this file for day to day laboratory activities.