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Answer:
A few points need to be clarified so you're not mixing apples and oranges. CPT 2009 deleted modifier 21, which was a prolonged service modifier that could be used on only the highest E/M level in a given category. You could use modifier 21 on only 99205 (New patient office visit), 99215, 99233 (Subsequent hospital care ...), etc. (highest time based code in a series).Now, the highest category restriction pertains to +99354 and +99355 in only one situation: time based E/M coding. When you're using time based coding because counseling and/or coordination of care dominates the service, you have to code based on the service's total face-to-face time. Since you would select the code based on the total time, you would only use prolonged services if you had reached the threshold for the highest level code and still had uncaptured minutes totaling 30 minutes or more.
Let's look at your example of a 60 minute established patient office visit. If you spent and documented more than 30 minutes on counseling/coordination of care, you would select 99215.
You would only have 20 more uncaptured minutes, which you could not capture using the prolonged services codes, because prolonged services less than 30 minutes are not reported separately. If, however, you performed 99214 based on the service's key components of history, exam, and medical decision making, but the visit for some medically necessary documented reason took 60 minutes rather than the average 25 minutes that physicians usually spend performing this service, you would code 99214 and +99354 to capture the additional uncaptured 35 minutes.
So you can use +99354 on 99211-99214 provided you are selecting the base code based on HEM, not time. When selecting the code based on time, you bill the highest level (e.g., 99215) and then use a prolonged service code to capture any additional time that is 30 minutes or more over the typical minutes involved with the highest level.