Question: We perform intravenous sympathetic regional blocks for complex regional pain syndrome, but how should we code for them? They take longer than the normal nerve block codes, so it does not seem right to use those. Wisconsin Subscriber Answer: You are correct in foregoing the standard nerve block codes (64400-64530) because they apply to injections and your physician is administering an IV. Because the regional blocks are administered intravenously, the most accurate code would be 90784 (Therapeutic, prophylactic or diagnostic injection [specify material injected]; intravenous). You should identify the drugs used in the intravenous line by using the appropriate HCPCS code.