This is an area many people dont understand. You have three key components. History, Exam and Medical Decision Making.
You need to look at the E/M code you wish to select. Look to see if you need 2 out of the 3 key components or do you need all three key components to select the E/M. Office visits for new patients usually require all 3 key components. Emergency E/M requires all 3.
So, you have 3 different levels before you. You have an Expanded Problem Focused (EPF) History, A detailed Examination, and a High Medical Decision Making (MDM). So, what E/M level do you select???
Another way of looking at this is steps. You have 3 people. Larry Moe and Curley. To select the level of stairs is that all 3 people have to be on the same level of steps at the same time. Larry only has 1 step. Moe has 2 steps and Curley has 5 steps. Larry cant go any higher because all he has is 1 step. Moe has 2 steps, so to be at the same level as Larry, he walks down 1 step and stands beside Larry at the first step. Curley has to go down 4 steps to stand beside Larry and Curley on step 1.
Get back to the E/M.
YOU have EPF History (2 steps), you have detailed examination (3 steps) and you have High MDM (5 steps), larry is at step 2 and cant go higher. Moe and Curley step down until they are side by side with Larry at Step 2. You look and see that step 2 is 99202.
Lets say you need 2 out of 3 at the same level as with an established office visit patient.
Larry is at step 2. Moe is at 3 steps, and Curley is at 5 steps. Curley can go down a few steps until he is standing at the same step as Moe. 2 out of the 3 stooges are now at the same level.
Lets do a few fun examples:
This is an Emergency Department Visit (3/3 required)
Larry (History) EPF (99282)
Moe (Exam) EPF (99282)
Curley (MDM) High (99285)
Curley drops down to step 99282 so your E/M would be 99282
Larry (History) EPF (99282)
Moe (Exam) Detailed (99284)
Curley (MDM) High (99285)
Moe and Curley drop down to step 99282 so your E/M would be 99282
Larry (History) Comprehensive (99285)
Moe (Exam) Detailed (99284)
Curley (MDM) Problem Focused (99281)
Moe and Curley drop down to step 99281 so your E/M would be 99281
I hope this helps