7.2 CMS-1500 (Professional) Claim
Key Takeaways
- The CMS-1500 is the standard paper claim form for professional (physician and non-institutional) services; its electronic equivalent is the 837P.
- Box 21 holds up to 12 ICD-10-CM diagnosis codes, and Box 24E links each service line to the relevant diagnosis pointer.
- Box 24B carries the Place of Service (POS) code, which tells the payer where the service occurred and affects the fee schedule.
- Box 33 identifies the billing provider (pay-to entity and NPI), while Box 32 identifies the service facility location when different.
- Box-level errors — wrong POS, missing NPI, mismatched diagnosis pointers — are a leading cause of professional claim rejections.
Purpose of the CMS-1500
The CMS-1500 is the standardized claim form for professional services — physicians, non-physician practitioners, ambulance suppliers, durable medical equipment suppliers, and other non-institutional providers. It is maintained by the National Uniform Claim Committee (NUCC). Its electronic equivalent is the 837P (P for professional), the HIPAA transaction used for nearly all real-world submission.
The form has 33 numbered boxes (fields) divided into three zones: carrier/patient information (Boxes 1–13), physician/supplier information (Boxes 14–33), and the service-line grid (Box 24).
Key Fields Billers Must Know
| Box | Field | What It Carries |
|---|---|---|
| 11d | Another health benefit plan | "Yes" triggers coordination of benefits; secondary insurer data goes in 9a–9d |
| 17 | Referring/ordering provider | Name of the referring or ordering provider; 17b holds that provider's NPI |
| 21 | Diagnosis codes | Up to 12 ICD-10-CM codes, labeled A–L; ICD indicator "0" denotes ICD-10 |
| 24A | Date(s) of service | From/to dates for each service line |
| 24B | Place of Service (POS) | Two-digit code for where the service occurred |
| 24D | Procedures/services | CPT or HCPCS code plus modifiers |
| 24E | Diagnosis pointer | Letter(s) linking the line to Box 21 diagnoses |
| 24F | Charges | Billed amount for the line |
| 24G | Days or units | Quantity (units, minutes, miles) |
| 24J | Rendering provider NPI | NPI of the provider who performed the service |
| 25 | Federal Tax ID | Practice EIN or SSN, with the matching box checked |
| 31 | Provider signature | Signature of physician or supplier |
| 32 | Service facility location | Name, address, and NPI of where service was rendered |
| 33 | Billing provider | Pay-to provider name, address, phone, and NPI (33a) |
Place of Service (POS) Codes
The POS code in Box 24B tells the payer the setting of care, which can change the allowed amount on the fee schedule. Common POS codes:
| POS | Setting |
|---|---|
| 11 | Office |
| 12 | Home |
| 21 | Inpatient hospital |
| 22 | On-campus outpatient hospital |
| 23 | Emergency department – hospital |
| 31 | Skilled nursing facility (SNF) |
| 32 | Nursing facility (NF) |
| 81 | Independent laboratory |
Common Box-Level Errors
- Wrong or missing POS — billing an office POS (11) for a service done in a hospital (21) misprices the claim.
- Invalid diagnosis pointer in 24E that points to a Box 21 letter that has no code.
- Missing rendering NPI in 24J or billing NPI in 33a.
- Box 11d marked "Yes" without completing the secondary insurance fields, or marked "No" when a secondary payer exists.
- Referring provider required for certain services (lab, imaging) but Box 17/17b left blank.
A biller is preparing a claim for an office-based physician visit. On the CMS-1500, which box holds the Place of Service code and which two-digit code represents an office?
A claim is rejected because Box 24E points to diagnosis letter "C," but Box 21 only contains codes in positions A and B. What kind of error is this?