The HCPCS modifier EJ is used for billing the subsequent doses in a defined course of therapy. It is not used for the first dose or injection of a series. Common applications Compounded Cyanocobalamin (Vitamin B12) Injection Empower CPT 96372 Code Guide: Injections, Billing, Documentation and Reimbursement CPT 96372: Injection Billing Made Simple for Medical Practices Billing CPT Code 96372 Accurate Injection Claim Guide Vitamin B 12 5000 mcg Injection 100mL