> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rcintell.com/llms.txt
> Use this file to discover all available pages before exploring further.

# L5: Service group

> Classify CPT codes into service groups with group-specific documentation requirements, modifier rules, and global periods

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:

| CPT prefix  | Service group             | Example codes       |
| ----------- | ------------------------- | ------------------- |
| 992xx-994xx | Evaluation & Management   | 99213, 99284, 99232 |
| 10000-69999 | Surgical Procedures       | 27447, 43239, 29881 |
| 70000-79999 | Radiology & Imaging       | 71046, 74177, 77067 |
| 80000-89999 | Pathology & Laboratory    | 80053, 85025, 88305 |
| 90000-99199 | Medicine                  | 90471, 96372, 93000 |
| 00100-01999 | Anesthesia                | 00142, 01402, 01967 |
| A-L codes   | Durable Medical Equipment | E0601, L3000, A4253 |

## Request

```bash theme={null}
curl "https://api-dev.rcintell.com/v1/knowledge/layers/170001/l5?cpt=99213" \
  -H "X-API-Key: $RCI_API_KEY"
```

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

## Response

```json theme={null}
{
  "layer": "l5_service_group",
  "data": {
    "service_group_key": "em",
    "name": "Evaluation & Management",
    "cpt_range": "99202-99499",
    "documentation": "Medical decision-making (MDM) or total time",
    "key_modifiers": [
      "25 (significant, separately identifiable E/M)",
      "57 (decision for surgery)"
    ],
    "split_shared_rules": true,
    "teaching_physician_rules": true
  }
}
```

## Service group rules

Each group has unique billing characteristics that affect reimbursement:

<CardGroup cols={2}>
  <Card title="E/M (99202-99499)" icon="stethoscope">
    Documented by medical decision-making complexity or total time. Split/shared visit rules and teaching physician rules apply. Key modifier: 25.
  </Card>

  <Card title="Surgical (10000-69999)" icon="scalpel">
    Requires operative report. Global periods of 0, 10, or 90 days include follow-up visits. Multiple procedure reduction (MPPR) at 50% on secondary procedures.
  </Card>

  <Card title="Radiology (70000-79999)" icon="x-ray">
    Component billing: modifier 26 (professional) and TC (technical). Requires order with clinical indication.
  </Card>

  <Card title="Anesthesia (00100-01999)" icon="clock">
    Payment = (Base units + Time units + Modifying units) × Conversion factor. Requires anesthesia record with start/stop times.
  </Card>
</CardGroup>

## Key modifiers by group

| Group          | Modifier | Description                                                       |
| -------------- | -------- | ----------------------------------------------------------------- |
| **E/M**        | 25       | Significant, separately identifiable E/M on same day as procedure |
| **E/M**        | 57       | Decision for surgery — E/M that leads to major surgery            |
| **Surgical**   | 50       | Bilateral procedure                                               |
| **Surgical**   | 51       | Multiple procedures (triggers MPPR)                               |
| **Surgical**   | 59       | Distinct procedural service                                       |
| **Surgical**   | 78       | Unplanned return to OR during global period                       |
| **Surgical**   | 79       | Unrelated procedure during postoperative period                   |
| **Radiology**  | 26       | Professional component only                                       |
| **Radiology**  | TC       | Technical component only                                          |
| **Anesthesia** | AA       | Anesthesiologist personally performed                             |
| **Anesthesia** | QK       | CRNA under medical direction                                      |
| **Anesthesia** | QZ       | CRNA without medical direction                                    |

## Global periods

Surgical procedures include a post-operative global period during which follow-up visits are bundled into the surgical payment:

| Global period | Meaning                                | Example                              |
| ------------- | -------------------------------------- | ------------------------------------ |
| **0 days**    | Only the procedure day is included     | Minor procedures, endoscopies        |
| **10 days**   | 10-day post-op follow-up included      | Minor surgical (skin lesion removal) |
| **90 days**   | 1-day pre-op + 90-day post-op included | Major surgery (27447 total knee)     |
| **XXX**       | Global concept does not apply          | E/M visits, lab, radiology           |

<Warning>
  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.
</Warning>

## Documentation requirements

| Group      | Required documentation                                           |
| ---------- | ---------------------------------------------------------------- |
| E/M        | Medical decision-making (MDM) level or total time documentation  |
| Surgical   | Operative report with procedure details                          |
| Radiology  | Order with clinical indication; interpretation report            |
| Pathology  | Order with medical necessity; CLIA certification                 |
| Anesthesia | Anesthesia record with start/stop times, medications, monitoring |
| DME        | Certificate of Medical Necessity (CMN) for qualifying items      |