Where coding denials come from
Coding denials rarely come from the wrong diagnosis. They come from detail. In psychiatry, add-on psychotherapy codes fail on documentation detail (CO-16). For nurse practitioners, add-ons absorb into the base code unless modifiers are exact (CO-97). In telehealth, modifier and place-of-service pairs change payer by payer (CO-4).
Each of those is specialty knowledge. A coder who doesn't know the pattern will keep producing the same denial.
What our coding review includes
- CPT and HCPCS procedure codes against the visit note
- ICD-10 diagnosis codes and their linkage to each line
- Modifiers, including payer-specific telehealth rules
- Bundling and add-on code checks
- Documentation gaps sent back to the provider before submission
Coding that learns from denials
Because we also work the denials, coding rules are updated from what payers actually reject. When a modifier pattern starts failing with one payer, the change lands in coding the same month — not after a quarter of lost revenue.
E/M levels, add-on codes and modifiers
Office visits are billed with evaluation and management (E/M) codes — 99202–99215 for outpatient visits — and the level is chosen by medical decision making or by total time on the date of the encounter. Under-coding leaves earned revenue unbilled; over-coding creates audit and repayment risk. We check the level against what the note supports, not against habit.
Add-on codes are where specialty billing is won or lost. Psychotherapy with an E/M visit (90833, 90836, 90838) needs separately documented psychotherapy time. Procedures done at the same visit as an E/M often need modifier 25 on the visit, and distinct procedures may need modifier 59 or an X modifier. Telehealth adds its own place-of-service codes and modifiers such as 95, which payers apply differently.
Documentation queries, not guesses
When a note doesn't support the code the provider selected, we don't change the code to fit and we don't submit it hoping for the best. The query goes back to the provider with the specific detail that is missing, and recurring gaps are reported monthly so templates can be changed once rather than queried forever.