| E/M upcoding | Level by medical decision making or total time on the date of the encounter (2021 office, 2023 facility rules); documentation must support the elements | Templates that pre-populate high-complexity MDM; "99214 for everything"; time claimed that exceeds plausible schedules; AI-drafted notes that document more than was done | Provider-level distribution versus specialty peers; chart audit of 10–20 encounters per provider per year; template review |
| Unbundling and NCCI | NCCI procedure-to-procedure edits and medically unlikely edits define what is included in another code | Billing components separately; appending a modifier to bypass an edit without a distinct service | Edit override report: who bypassed which edit with what modifier; sample the overrides |
| Modifier 25 | Significant, separately identifiable E/M on the same day as a minor procedure, beyond the procedure's usual pre- and post-work | E/M billed with every injection, skin lesion removal or test; the note describes only the procedure | Modifier 25 rate by provider; audit the E/M note for a separate problem and work |
| Modifier 59 and X{EPSU} | Distinct procedural service: different session, site, organ system, incision, lesion or injury | Used as the default edit bypass; applied by a scrubber rule rather than a coder reading the note | 59 and XS/XU rate versus peers; prohibit automated 59 rules; audit a sample |
| Incident-to | 42 CFR 410.26: service by auxiliary personnel integral to the physician's plan of care, in a non-facility setting, under direct supervision (physician in the office suite, immediately available), billed under the physician for an established problem | New problems addressed by an NP billed under the physician; physician off site; billing incident-to in a hospital department; no documented plan of care | Schedule cross-check: supervising physician's location on the date; billing provider versus rendering provider report |
| Split or shared visits | 42 CFR 415.140: facility-setting E/M shared by a physician and an NPP in the same group; billed by whoever performed the substantive portion (more than half the total time, or a substantive part of the MDM; critical care by time only); modifier FS required. CY 2026 PFS kept this definition | Physician billing after a brief sign-off; missing FS; both practitioners billing | FS modifier use; audit for the substantive portion documentation and both practitioners' attestations |
| Teaching physician services | 42 CFR 415.172: physician must be present for the key portion of the service (or meet the primary care exception) and document participation; since CY 2026 virtual presence via real-time audio-video is permitted in all training settings | Resident-only services billed under the attending; macro attestations with no personal involvement | Attestation language audit; GC/GE modifier use; resident schedules |
| Cloned and copied documentation | Each encounter's note must reflect that encounter; copied text that is not updated does not support the service | Identical exam and plan across visits; prior-day vitals; "patient states" copied from a year ago | EHR copy-forward audit tools; sample notes for identical blocks |
| Medical necessity and ABNs | Medicare pays only reasonable and necessary services (SSA 1862(a)(1)(A)); LCD and NCD coverage rules; an ABN shifts liability only when properly executed before the service | Diagnosis codes chosen to pass an LCD edit rather than from the record; blanket ABNs; GA modifier without a signed ABN on file | LCD-driven denial trends; ABN audit (timing, signature, specific service and reason) |
| Credit balances and duplicates | 60-day rule; CMS-838 quarterly report; payer contract refund terms | Credits aged over 90 days; credits netted against unrelated debits; duplicate payments retained | Credit balance aging by payer; refund turnaround; CMS-838 reconciliation |
| Place of service and provider identity | POS must match where the service occurred; rendering NPI must be who performed it; locum and reciprocal rules (Q5/Q6) are time-limited | Office POS for hospital outpatient services to get the higher non-facility rate; billing under a credentialed physician for a non-credentialed one | POS versus facility fee claims; rendering NPI versus schedule; credentialing status at date of service |
| Time-based services | Prolonged services, therapy units (8-minute rule for Medicare), care management, critical care, anesthesia time all require documented time | Units that imply more hours than the provider worked; rounding up; overlapping times across patients | Provider time totals per day versus hours worked; overlap report |
| Telehealth | Statutory flexibilities have been extended in short increments since 2020; modifiers (95, 93), POS 02/10, audio-only and originating site rules change by date | Billing in-person codes for audio-only calls; wrong POS; services outside the covered list for the date | Date-sensitive edit table; sample telehealth claims each quarter |
| Risk adjustment diagnoses | Medicare Advantage and ACA diagnoses must be documented in a face-to-face encounter and supported (MEAT: monitored, evaluated, assessed, treated) | Chart reviews that add codes without clinical support; suspect-condition lists pushed to providers; unsupported HCCs in problem lists carried forward | RADV-style audit of a sample of submitted HCCs; one-way (add-only) review programs are a red flag DOJ has named |