> ## 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 Rules Network

> Open catalog of billing forms, type-of-bill codes, place-of-service codes, modifiers, and NCCI edits — searchable and cross-referenced

> The open reference for healthcare billing rules. Browse, search, cross-reference. Free.

The Billing Rules Network is RCI's open catalog of billing requirements. Like Stedi's EDI Network is for trading partner specifications, the Billing Rules Network is for billing logic — every code, every form, every modifier, cross-referenced.

**Browse it at [rcintell.com/tools](https://rcintell.com/tools)**

## What's in the Billing Rules Network

### Type of Bill (TOB) Codes

Every institutional claim requires a 4-digit Type of Bill code. The first digit is always `0`.

| 2nd Digit (Facility)     | 3rd Digit (Classification)                 | 4th Digit (Frequency)       |
| ------------------------ | ------------------------------------------ | --------------------------- |
| 1 = Hospital             | 1 = Inpatient (Part A)                     | 1 = Admit through discharge |
| 2 = SNF                  | 2 = Inpatient (Part B)                     | 2 = Interim - first claim   |
| 3 = Home Health          | 3 = Outpatient                             | 3 = Interim - continuing    |
| 4 = Religious Nonmedical | 4 = Other (Part B)                         | 4 = Interim - last claim    |
| 5 = (Reserved)           | 5 = Intermediate care (Level I)            | 5 = Late charge only        |
| 6 = Intermediate care    | 6 = Intermediate care (Level II)           | 7 = Replacement             |
| 7 = Clinic               | 7 = Subacute inpatient (Revenue code 019x) | 8 = Void/cancel             |
| 8 = Special facility     | 8 = Swing bed                              | 9 = Final claim for HH PPS  |
| 9 = (Reserved)           | 9 = (Reserved)                             | 0 = Non-payment/zero        |

**Common combinations:**

| TOB  | Meaning                                       | When to use                     |
| ---- | --------------------------------------------- | ------------------------------- |
| 0111 | Hospital Inpatient (admit through discharge)  | Standard inpatient stay         |
| 0121 | SNF Inpatient (admit through discharge)       | Standard SNF stay               |
| 0131 | Hospital Outpatient                           | Outpatient services at hospital |
| 0321 | Home Health (Part A)                          | HH services under Part A        |
| 0341 | Home Health (Part B)                          | HH services under Part B        |
| 0711 | Clinic - Rural Health Clinic                  | RHC services                    |
| 0831 | Special facility - Ambulatory Surgical Center | ASC services                    |

### Place of Service (POS) Codes

Every professional claim requires a POS code.

| Code | Name                           | Modifier Impact | Site-of-Service Differential |
| ---- | ------------------------------ | --------------- | ---------------------------- |
| 11   | Office                         | Standard rates  | Non-facility rate            |
| 19   | Off-campus outpatient hospital | 27 modifier     | Facility rate                |
| 21   | Inpatient hospital             | -               | Facility rate                |
| 22   | On-campus outpatient hospital  | -               | Facility rate                |
| 23   | Emergency room                 | -               | Facility rate                |
| 24   | Ambulatory surgical center     | -               | ASC rate                     |
| 25   | Birthing center                | -               | Non-facility rate            |
| 31   | Skilled nursing facility       | -               | Facility rate                |
| 32   | Nursing facility               | -               | Facility rate                |
| 81   | Independent laboratory         | -               | Non-facility rate            |

### Modifier Reference

Modifiers affect payment, processing, and compliance.

| Modifier | Name                                     | When to use                              | Payment impact              |
| -------- | ---------------------------------------- | ---------------------------------------- | --------------------------- |
| 25       | Significant, separately identifiable E/M | E/M same day as procedure                | Allows separate E/M payment |
| 26       | Professional component                   | Interpreting only (no equipment)         | Prof fee only               |
| TC       | Technical component                      | Equipment/staff only (no interpretation) | Tech fee only               |
| 59       | Distinct procedural service              | Unbundling when appropriate              | Allows separate payment     |
| XE       | Separate encounter                       | More specific than 59                    | Allows separate payment     |
| XS       | Separate structure                       | More specific than 59                    | Allows separate payment     |
| XP       | Separate practitioner                    | More specific than 59                    | Allows separate payment     |
| XU       | Unusual non-overlapping service          | More specific than 59                    | Allows separate payment     |
| 76       | Repeat procedure by same physician       | Same day repeat                          | Allows separate payment     |
| 77       | Repeat procedure by another physician    | Different physician repeat               | Allows separate payment     |
| 22       | Increased procedural services            | Extra work documentation                 | May increase payment        |
| 52       | Reduced services                         | Procedure not completed                  | Reduces payment             |

### NCCI Edits

National Correct Coding Initiative edits determine which procedures can be billed together.

| Column 1 | Column 2 | Modifier Indicator | Meaning                       |
| -------- | -------- | ------------------ | ----------------------------- |
| 99213    | 36415    | 1                  | Can unbundle with modifier    |
| 99213    | 81002    | 0                  | Cannot unbundle               |
| 43239    | 43235    | 0                  | Column 2 included in Column 1 |
| 29881    | 29880    | 0                  | Column 2 included in Column 1 |

**Modifier indicators:**

* `0` = never allowed to unbundle
* `1` = modifier allowed if criteria met (typically mod 59 or XE/XS/XP/XU)
* `9` = not applicable

### Billing Form Reference

| Form     | Use                  | Who files             | Key fields                     |
| -------- | -------------------- | --------------------- | ------------------------------ |
| CMS-1500 | Professional claims  | Physicians, NPPs, DME | POS, modifier, diagnosis       |
| UB-04    | Institutional claims | Hospitals, SNFs, HH   | TOB, revenue code, value codes |
| ADA      | Dental claims        | Dentists              | Tooth number, surface, area    |

### Revenue Code Reference

Revenue codes on UB-04 identify the type of service.

| Code      | Description                                | Common use                 |
| --------- | ------------------------------------------ | -------------------------- |
| 0100-0109 | Room & board (all-inclusive)               | All-inclusive room charges |
| 0110-0119 | Room & board (semi-private)                | Semi-private room          |
| 0120-0129 | Room & board (private)                     | Private room               |
| 0250-0259 | Pharmacy                                   | Drug charges               |
| 0260-0269 | IV therapy                                 | IV drug administration     |
| 0300-0309 | Laboratory                                 | Lab tests                  |
| 0320-0329 | Radiology - diagnostic                     | X-rays, CTs                |
| 0450-0459 | Emergency room                             | ER services                |
| 0510-0519 | Clinic                                     | Outpatient clinic visits   |
| 0636      | Pharmacy - drugs requiring detailed coding | Self-administered drugs    |
| 0761      | Treatment/observation room                 | Observation stays          |

## Searchable and cross-referenced

Every code links to related codes, required companion codes, exclusions, and real-world usage patterns:

* TOB links to valid revenue codes and facility types
* POS links to modifier requirements and payment differentials
* Modifiers link to NCCI edits that accept them
* Revenue codes link to valid TOB ranges

## API access

```bash theme={null}
# Look up a TOB code
curl https://api-dev.rcintell.com/v1/knowledge/billing-rules/tob/0131 \
  -H "X-API-Key: kp_test_..."

# Look up a POS code
curl https://api-dev.rcintell.com/v1/knowledge/billing-rules/pos/22 \
  -H "X-API-Key: kp_test_..."

# Check NCCI edits for a CPT pair
curl https://api-dev.rcintell.com/v1/knowledge/billing-rules/ncci?column1=99213&column2=36415 \
  -H "X-API-Key: kp_test_..."

# Search modifiers
curl https://api-dev.rcintell.com/v1/knowledge/billing-rules/modifiers?q=separate \
  -H "X-API-Key: kp_test_..."
```

## Free to browse

The Billing Rules Network is free and publicly accessible at [rcintell.com/tools](https://rcintell.com/tools). No account required to browse. API access requires a free API key.