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Layer 5 classifies a CPT code into its service group — E/M, surgical, radiology, pathology, anesthesia, or DME. Each group has fundamentally different billing rules, documentation requirements, and modifier behavior.

How classification works

The resolver uses the CPT code prefix to determine the service group:

Request

L5 requires a cpt parameter. Without it, the layer cannot determine the service group and returns a note indicating it was skipped.

Response

Service group rules

Each group has unique billing characteristics that affect reimbursement:

E/M (99202-99499)

Documented by medical decision-making complexity or total time. Split/shared visit rules and teaching physician rules apply. Key modifier: 25.

Surgical (10000-69999)

Requires operative report. Global periods of 0, 10, or 90 days include follow-up visits. Multiple procedure reduction (MPPR) at 50% on secondary procedures.

Radiology (70000-79999)

Component billing: modifier 26 (professional) and TC (technical). Requires order with clinical indication.

Anesthesia (00100-01999)

Payment = (Base units + Time units + Modifying units) × Conversion factor. Requires anesthesia record with start/stop times.

Key modifiers by group

Global periods

Surgical procedures include a post-operative global period during which follow-up visits are bundled into the surgical payment:
Billing an E/M visit during a surgical global period without modifier 24 (unrelated E/M during postop) or 79 (unrelated procedure) will result in denial. Check the global period from L5/L6 before billing post-operative visits.

Documentation requirements