Im practice in Tempe, AZ looking for advise on what the actual threshold time are on billing prolonged visits code 99354. We thought the threshold time for a 99214 and 99354 was a total of 55 minutes. But after research we found that medicare states that a 99354 is only billable 60 minutes beyond the initial time for 99214 (30 minutes) is a 99215 be replaced???? Really appreciate any advise, experience or input on this matter - look forward to hearing from my IM Coders out there!! thank you