Question: How should I code a Bier block? Should I use an unlisted-procedure code such as 64999? Wisconsin Subscriber Answer: Bier block coding is a gray area that each coder handles differently. Many coders frequently use 64450* (Injection, anesthetic agent; other peripheral nerve or branch) for Bier blocks, but others report unlisted-procedure code 64999 (Unlisted procedure, nervous system) instead. Check the carrier's guidelines for Bier block coding so you can submit the claim correctly.