> ## 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.

# L3: Care setting

> Resolve place of service codes, modifier requirements, and facility vs. non-facility payment rates

Layer 3 determines the care setting context — where the service is actually being delivered — which directly affects place of service (POS) codes, required modifiers, and whether the facility or non-facility PE RVU applies to the payment calculation.

## How L3 depends on L2

L3 uses the facility type from L2 to infer a default care setting when you don't specify one:

| L2 facility type       | Default care setting | POS code |
| ---------------------- | -------------------- | -------- |
| Short-term acute / CAH | `inpatient`          | 21       |
| Home health            | `home_health`        | 12       |
| SNF                    | `snf`                | 31       |
| FQHC                   | `office`             | 50       |
| Other                  | `outpatient`         | 22       |

You can override the default by passing `care_setting` in the resolve request — for example, a short-term hospital may deliver services in an outpatient department (POS 22) rather than inpatient (POS 21).

## Request

```bash theme={null}
curl https://api-dev.rcintell.com/v1/knowledge/layers/170001/l3 \
  -H "X-API-Key: $RCI_API_KEY"
```

Or within a full resolution with an explicit care setting:

```bash theme={null}
curl -X POST https://api-dev.rcintell.com/v1/knowledge/resolve \
  -H "X-API-Key: $RCI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "ccn": "170001",
    "cpt": "99213",
    "care_setting": "outpatient"
  }'
```

## Response

```json theme={null}
{
  "layer": "l3_care_setting",
  "data": {
    "care_setting": "outpatient",
    "place_of_service": [
      {
        "name": "On Campus - Outpatient Hospital",
        "description": "Hospital-based outpatient",
        "facility_indicator": true
      }
    ],
    "modifier_requirements": [
      "Site-of-service differential applies",
      "May need modifier 27"
    ],
    "typical_tob": "013x",
    "admission_required": false
  }
}
```

## Place of Service codes

POS codes tell the payer where the service was rendered:

| POS | Name                | Facility? | Payment impact                       |
| --- | ------------------- | --------- | ------------------------------------ |
| 11  | Office              | No        | Non-facility PE RVU (higher payment) |
| 12  | Home                | No        | Non-facility PE RVU                  |
| 21  | Inpatient Hospital  | Yes       | Facility PE RVU (lower payment)      |
| 22  | Outpatient Hospital | Yes       | Facility PE RVU                      |
| 23  | Emergency Room      | Yes       | Facility PE RVU                      |
| 31  | SNF                 | Yes       | Facility PE RVU                      |
| 50  | FQHC                | Yes       | All-inclusive rate                   |

<Note>
  The "Facility?" column determines which PE RVU is used in the L6 payment calculation. Facility settings use the lower PE RVU because the facility absorbs overhead costs. Non-facility settings use the higher PE RVU because the physician's practice bears those costs.
</Note>

## Site-of-service differential

The same CPT code pays differently depending on the POS. For CPT 99213:

| Setting                      | PE RVU              | Total payment (KS) |
| ---------------------------- | ------------------- | ------------------ |
| Hospital outpatient (POS 22) | 0.99 (facility)     | \$75.00            |
| Physician office (POS 11)    | 1.81 (non-facility) | \$102.35           |

The \$27.35 difference is the site-of-service differential. This reflects that hospital-based physicians don't bear the same overhead as office-based physicians — the hospital does.

<Warning>
  Billing an office visit (POS 11) when the service was actually rendered in a hospital outpatient department (POS 22) is a compliance risk. POS must match the actual location of service.
</Warning>

## Modifier requirements by setting

Each care setting has specific modifier rules:

| Care setting | Common modifiers | Notes                                                   |
| ------------ | ---------------- | ------------------------------------------------------- |
| Inpatient    | 25, 59           | Distinct services need modifier separation              |
| Outpatient   | 27               | Outpatient hospital E/M on same day as procedure        |
| Home health  | —                | LUPA adjustments apply for low-utilization episodes     |
| SNF          | —                | Part A consolidated billing applies during covered stay |
| Office       | —                | Non-facility rate applies; standard E/M rules           |

## Care setting values

Pass one of these values in the `care_setting` parameter:

| Value         | Description                          |
| ------------- | ------------------------------------ |
| `inpatient`   | Acute inpatient admission            |
| `outpatient`  | Hospital outpatient department       |
| `office`      | Physician or provider office         |
| `home_health` | Patient's home (home health episode) |
| `snf`         | Skilled nursing facility stay        |