October 14, 2021

Question:
My Mohs surgeon was performing Mohs surgery on the scalp and completed stage 1 and 2 but cancer was still evident in the margins.  The patient needed a third stage but could not tolerate the third stage on the same date.  The patient came back the next day and the physician performed stage 3.    Do I report 17211 and 17312 on day 1 and 17312 on day 2?  I am not sure if this is correct.  What do you think?

Answer:
When the patient cannot tolerate an additional stage and the physician elects to have the patient come back for an additional stage the following day, you must start with the primary code (CPT code 17311) on day two. Insurance carrier computer edits will reject claims where a secondary code (e.g., CPT code 17312) is billed without the primary code (e.g., CPT code 17311). Since Mohs has 0 global days for Medicare the appropriate way to code this claim would be: Day 1: 17311 (stage 1); 17312 (stage 2); Day 2: 17311 (stage 3)

It is recommended that the physician document the reason stage 3 was not performed on the initial date of the Mohs procedure to support medical necessity.

*This response is based on the best information available as of 10/14/21.