Type of Bill (TOB) 131 on a UB-04 claim form signals a hospital-based outpatient encounter that started in the emergency room and ended with discharge or transfer. The digits never change: the first is always “0,” the second “1” for hospital, the third “3” for outpatient care, and the fourth “1” for the one and only bill in that episode. As of 2026, Medicare, Medicaid, and most private insurers still expect TOB 131 when the patient walks in through the ER, gets outpatient services, and walks out without ever being admitted as an inpatient.
Quick Fix Summary
If your claim keeps getting rejected, triple-check the fourth digit is “1,” the third digit is “3,” and the second digit is “1.” Fix the form, slap on the right revenue code for every service, and send it back in.
What’s Happening
TOB 131 is a four-digit bill type on the UB-04 (CMS-1450) form that tells the payer exactly how the episode of care started and ended.
| Position | Digit value | Meaning |
|---|---|---|
| 1 | 0 | Leading zero (required by NUBC) |
| 2 | 1 | Hospital facility |
| 3 | 3 | Outpatient care |
| 4 | 1 | Single claim for this episode (no interim claims) |
Because the whole visit began in the ER and wrapped up with discharge, TOB 131 is the code hospitals use when an outpatient claim covers everything from ER check-in to final checkout.
Step-by-Step Solution
Open the UB-04 form inside your billing software—think Meditech v6.1 or Epic Cadence 2025.2.1.
Head straight to Form Locator 4 (FL 4), the Type of Bill field.
Type 0131—zero-one-three-one—no spaces, no dashes, no exceptions.
Make sure the admit date in FL 6 matches the exact ER registration time.
For every service, drop the correct revenue code—0450 for clinic visits, 0762 for lab tests—in FL 42-49.
Save the file, export either an 837-I or 837-P, and fire it off through your usual clearinghouse.
If This Didn’t Work
Wrong frequency digit: If the patient comes back within 30 days, switch to TOB 133 (interim continuing) or 134 (interim last).
Service mix mismatch: If any inpatient charges sneak in, jump to TOB 111 (inpatient admit-through-discharge) and tack on modifier –TC for the technical component.
Missing revenue codes: Pull the latest revenue-code list from the National Uniform Billing Committee (NUBC, updated March 2026) and double-check every service.
Prevention Tips
Get front-desk staff in the habit of asking three quick questions at registration: “Inpatient or outpatient?”, “ER arrival time?”, and “Discharge status?” Flag the account in your EHR with “TOB-131-ready” so coders never have to guess the digits. Once a month, run a scrub using the 2026 CMS quarterly NCCI edits to catch any mismatched TOB–revenue-code pairs before they leave the building.
