UB04 Type of Bill Code 0831: Specialty Facility - Ambulatory Surgery Center

Overview

The Type of Bill (TOB) code is a four-digit alphanumeric code used on the UB‑04 claim form. The leading zero is ignored by CMS, and the remaining three digits convey the facility type, care type, and claim frequency. ^[1] The second digit “8” indicates a special facility, which includes Ambulatory Surgery Centers (ASC) and Critical Access Hospitals (CAH). ^[1] The third digit “3” denotes outpatient care. ^[1] The fourth digit “1” means Admit Through Discharge – the claim covers the entire outpatient episode from admission to discharge. ^[1] Therefore, TOB 0831 is used by an Ambulatory Surgery Center to submit a single, complete outpatient claim for services provided during one visit. The MassHealth UB‑04 Billing Guide confirms that the UB‑04 form is required for paper claims from certain providers, and the Type of Bill field (Field 4) must be completed according to standard code sets. ^[2]

When to Use

This code is not appropriate for interim billing or late‑charge‑only submissions. When the ASC needs to bill in multiple interim claims, it would use 0832 (Interim – First Claim), 0833 (Interim – Continuing), or 0834 (Interim – Last Claim). ^[1] Late charges only would be coded 0835, replacements 0837, and voids 0838. ^[1] The leading zero is required on the UB‑04 form but is stripped by CMS during processing. ^[1]

Step-by-Step Claim Example

Scenario: A Medicare beneficiary receives a right knee arthroscopy at an ASC. The ASC submits a paper UB‑04 claim (or electronic equivalent) for this single outpatient encounter.

1. Field 4 – Type of Bill: Enter 0831. The “0” is the leading zero, “8” denotes ASC (special facility), “3” indicates outpatient, and “1” means admit through discharge. ^[1]
2. Field 6 – Statement Covers Period (From/Through): Enter the date of service (e.g., 01/15/2025 – 01/15/2025). The code “1” in TOB confirms this is a single‑stay claim.
3. Field 8 – Patient Name: Enter the patient’s full name as it appears on their insurance card.
4. Field 9d – Patient Control Number: Use the ASC’s internal account number.
5. Field 10 – Birth Date / Sex: Enter date of birth and sex.
6. Field 42 – Revenue Code: Use appropriate revenue codes for ASC services (e.g., 0490 for ambulatory surgical care, 0270 for medical/surgical supplies). Note: Revenue code definitions were not provided in the source texts; providers should refer to NUBC guidelines.
7. Field 43 – Description: Briefly describe the procedure (e.g., “Arthroscopy, right knee”).
8. Field 44 – HCPCS/Rates: Enter the applicable HCPCS code (e.g., 29881).
9. Field 47 – Total Charges: Sum all charges for the encounter.
10. Field 50 – Payer Name: Enter the primary payer (e.g., Medicare Part B).
11. Field 53 – COB Code / 54 – Payer ID: Complete according to payer requirements.
12. Field 56 – National Provider Identifier (NPI): Enter the ASC’s NPI.
13. Field 60 – Insured’s Unique ID: Enter the patient’s Medicare number.
14. Field 66 – Diagnosis Codes: List ICD‑10‑CM codes (e.g., M17.11).
15. Field 76 – Attending Provider: Enter the NPI of the surgeon.

The TOB code 0831 is derived solely from the Noridian bill‑type structure. ^[1]

Common Mistakes & Audit Red Flags

• Using 0831 for inpatient or hospital‑based services: The “8” facility digit is for special facilities only; hospitals use digit “1”. ^[1] Incorrect facility digit may lead to claim denial.
• Selecting the wrong frequency digit: If an ASC bills interim claims, 0831 is not valid. Use 0832 (first interim), 0833 (continuing), 0834 (last), or 0837 (replacement). ^[1]
• Omitting the leading zero: The UB‑04 requires a four‑digit code; “831” would be invalid. CMS expects the full “0831”. ^[1]
• Mixing outpatient and other care types: The third digit must be “3” for outpatient. Using “1” or “2” on an ASC claim is incorrect. ^[1]
• Submitting a late charge (0835) as 0831: Late‑charge‑only claims require a separate bill type. ^[1]
• Not updating the “From/Through” dates: For 0831, the dates must reflect a single continuous episode. Discrepancies may trigger audits.
• Failing to match the TOB to the provider type: Only ASCs and CAHs (for outpatient) can use facility digit “8”. Other specialty facilities (e.g., ESRD clinics) use digit “7”. ^[1]

Related Codes/Fields

Type of Bill	Description	Source
0831	ASC, outpatient, admit through discharge	[1]
0832	ASC, outpatient, interim – first claim	[1]
0833	ASC, outpatient, interim – continuing	[1]
0834	ASC, outpatient, interim – last claim	[1]
0835	ASC, outpatient, late charge only	[1]
0837	ASC, outpatient, replacement of prior claim	[1]
0838	ASC, outpatient, void/cancel of prior claim	[1]
0851	CAH, outpatient, admit through discharge (same structure, different facility)	[1]

Other relevant fields on the UB‑04: Field 4 (Type of Bill), Field 6 (Statement Covers Period), Field 42‑45 (Revenue Codes and HCPCS), Field 47 (Total Charges), Field 56 (NPI). These are general UB‑04 fields noted in the MassHealth guide. ^[2] For ASC billing, the revenue code range 0490‑0499 is typical for ambulatory surgical care, but revenue code specifics are not provided in the sourced documents.

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References

[1] Noridian Bill Types — https://med.noridianmedicare.com/web/jea/topics/claim-submission/bill-types

[2] MassHealth UB-04 Guide — https://www.mass.gov/doc/ub-04-billing-guide-0/download