OFFICE/OUTPATIENT E&M (99202-99215):
  Level based on MDM complexity OR total time on date of service

  MEDICAL DECISION MAKING (MDM):
    Straightforward (99202/99212):
      Problems: 1 self-limited or minor
      Data: minimal or none
      Risk: minimal (OTC meds, minor procedure no RF)

    Low complexity (99203/99213):
      Problems: 2+ self-limited, OR 1 stable chronic, OR 1 acute uncomplicated
      Data: limited (review/order tests, review external notes)
      Risk: low (Rx drug, minor procedure with RF)

    Moderate complexity (99204/99214):
      Problems: 1+ chronic illness with exacerbation/progression, OR undiagnosed new problem
      Data: moderate (review and summarize external records, independent interpretation)
      Risk: moderate (new Rx requiring monitoring, minor surgery with risk factors)

    High complexity (99205/99215):
      Problems: 1+ chronic illness with severe exacerbation, OR acute/chronic illness posing threat
      Data: extensive (independent interpretation + discussion with external physician)
      Risk: high (drug requiring intensive monitoring, elective major surgery with risk factors)

  TIME-BASED CODING (total time on date of service):
    99202/99212: 15-29 minutes
    99203/99213: 30-44 minutes
    99204/99214: 45-59 minutes
    99205/99215: 60-74 minutes
    Count: face-to-face + prep, documentation, coordination of care
    Do NOT count time for separately billable services

NEW vs ESTABLISHED:
  New: not seen by this physician OR same group/same specialty in 3 years
  Established: seen within 3 years
  When in doubt: code as new patient (higher work, need all components)

ED E&M (99281-99285):
  Always use new patient-equivalent documentation
  No new vs established distinction in ED
  Time does not drive level in ED (MDM only — pre-2021 3-component method)
  99285: high complexity (psychiatric crisis, multi-system trauma)

CRITICAL CARE (99291-99292):
  Requires physician direct delivery of care (not just supervision)
  First 30-74 minutes: 99291
  Each additional 30 minutes: 99292 (add-on)
  Cannot bill E&M on same day as critical care for same condition
  Time must be documented (start/stop or total minutes)

PROLONGED SERVICES (99417):
  For office E&M when time exceeds maximum of highest level
  99417: each additional 15 minutes beyond 99205/99215 time
  Must already be at highest level to add prolonged service

ENDOSCOPY RULES:
  Upper GI (43xxx): esophagus, stomach, duodenum
  Lower GI (45xxx): colon, rectum
  When multiple procedures during same endoscopy:
    List highest valued procedure first
    Other procedures get -51 modifier (if not add-on/exempt)
  Diagnostic colonoscopy becomes surgical: use surgical code + -33 (preventive)

MATERNITY CODING:
  Global OB package (59400/59510): antepartum, delivery, postpartum
  Antepartum only (59425/59426): if another physician delivers
  Vaginal delivery: 59400 | C-section: 59510
  VBAC: 59610 (vaginal after C-section) | Failed VBAC: 59618
  Additional procedures during delivery coded separately

OPHTHALMOLOGY:
  Eye exam codes: 92002/92004 (new) | 92012/92014 (established)
  Different from standard E&M — cannot bill both on same day
  Cataract: 66984 extracapsular vs 66982 complex
  Intravitreal injection: 67028 (anti-VEGF for macular degeneration)