Hmmmmm.....
Based on the word "discussion", I would not count writing a letter as a discussion. If the word was instead "correspond", then I would say it counts. By the current descriptions, my opinion is no.
If the letter is being written the day of the encounter, you can count the time spent toward your total clinician time.
Physician/other qualified health care professional time includes the following activities, when performed:
▪preparing to see the patient (eg, review of tests)
▪obtaining and/or reviewing separately obtained history
▪performing a medically appropriate examination and/or evaluation
▪counseling and educating the patient/family/caregiver
▪ordering medications, tests, or procedures▪referring and communicating with other health care professionals (when not separately reported)
▪documenting clinical information in the electronic or other health record
▪independently interpreting results (not separately reported) and communicating results to the patient/family/caregiver
▪care coordination (not separately reported)
If the letter is being written on a day other than the encounter day, 99358 may be an option. Although, I would have to say that would need to be some comprehensive letter to justify 30-74 minutes.