> ## 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.

# Billing guide

> Determine the correct billing form, type of bill codes, modifiers, and warnings for a facility and service

The `/v1/knowledge/billing-guide` endpoint consolidates billing rules from multiple knowledge layers into a single actionable guide. It tells you which form to use, what TOB codes apply, and flags potential billing issues before you submit a claim.

## Request

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

### Parameters

| Field      | Type      | Required | Description                                 |
| ---------- | --------- | -------- | ------------------------------------------- |
| `ccn`      | string    | Yes      | 6-digit Medicare Provider Number            |
| `cpt`      | string    | Yes      | CPT or HCPCS procedure code                 |
| `payer`    | string    | No       | Payer name (defaults to Medicare)           |
| `dx_codes` | string\[] | No       | ICD-10 codes for coverage context           |
| `modifier` | string    | No       | CPT modifier to validate (e.g., `25`, `59`) |

## Response

```json theme={null}
{
  "ccn": "170001",
  "cpt": "99213",
  "guidelines": [
    {
      "source": "l2_facility_type",
      "billing_form": "UB-04 (CMS-1450) / 837I"
    },
    {
      "source": "l2_facility_type",
      "type_of_bill": "013x"
    }
  ],
  "warnings": []
}
```

### What the billing guide resolves

| Field          | Source layer | Description                                               |
| -------------- | ------------ | --------------------------------------------------------- |
| `billing_form` | L2           | CMS-1500 (professional) or UB-04 (institutional)          |
| `type_of_bill` | L2           | 3-4 digit TOB code (e.g., `013x` for outpatient hospital) |
| `warnings`     | L2, L3       | Consolidated billing flags, exceptions, modifier notes    |

## Example: Home health agency

Home health agencies have specific consolidated billing rules that trigger warnings:

```bash theme={null}
curl -X POST https://api-dev.rcintell.com/v1/knowledge/billing-guide \
  -H "X-API-Key: $RCI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "ccn": "173001",
    "cpt": "99213",
    "payer": "Medicare"
  }'
```

```json theme={null}
{
  "ccn": "173001",
  "cpt": "99213",
  "guidelines": [
    {
      "source": "l2_facility_type",
      "billing_form": "UB-04 (CMS-1450) / 837I"
    },
    {
      "source": "l2_facility_type",
      "type_of_bill": "0329"
    }
  ],
  "warnings": [
    "Exceptions: 034x (osteoporosis drugs, dNPWT)",
    "Consolidated billing applies — check included services"
  ]
}
```

<Warning>
  When the response includes a consolidated billing warning, the facility is responsible for all covered services during the episode. Separately billing Part B services that fall under consolidated billing will result in denials.
</Warning>

## Common billing form rules

| Facility type             | Billing form | TOB (outpatient) | TOB (inpatient) |
| ------------------------- | ------------ | ---------------- | --------------- |
| Short-term acute hospital | UB-04 / 837I | 013x             | 011x            |
| Critical Access Hospital  | UB-04 / 837I | 085x             | 011x            |
| Home Health Agency        | UB-04 / 837I | 0329             | —               |
| Skilled Nursing Facility  | UB-04 / 837I | —                | 021x            |
| Hospice                   | UB-04 / 837I | —                | 081x            |
| FQHC                      | UB-04 / 837I | 077x             | —               |

<Note>
  The `x` in TOB codes represents the frequency digit (e.g., `0` = non-payment/zero claim, `1` = admit through discharge, `7` = replacement, `8` = void/cancel).
</Note>

## Using with modifiers

Pass a `modifier` parameter to validate whether the modifier is appropriate for the service and setting:

```bash theme={null}
curl -X POST https://api-dev.rcintell.com/v1/knowledge/billing-guide \
  -H "X-API-Key: $RCI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "ccn": "170001",
    "cpt": "99213",
    "modifier": "25",
    "payer": "Medicare"
  }'
```

Modifier 25 (significant, separately identifiable E/M service) is one of the most common — and most audited — modifiers. The billing guide will include modifier-specific warnings when applicable.