Overview
Type of Bill (TOB) is a three-digit numeric code on UB-04 institutional claims in Form Locator 04 identifying the nature of the bill. Each digit conveys specific information: the first digit identifies the facility type (e.g., hospital, skilled nursing facility, home health), the second digit identifies the bill classification (e.g., inpatient, outpatient), and the third digit identifies the frequency (e.g., interim bill, final bill, adjustment). The combined three-digit code communicates the institutional context required for appropriate claim adjudication.
First-digit facility types include: 1 (Hospital), 2 (Skilled Nursing Facility), 3 (Home Health), 4 (Religious Nonmedical Health Care Institution), 5 (Reserved), 6 (Intermediate Care), 7 (Clinic), 8 (Special Facility), 9 (Reserved). Most provider organizations use types 1, 2, 3, 7, or 8. Second-digit bill classifications depend on facility type; for hospitals, 1 (Inpatient Part A), 2 (Inpatient Part B), 3 (Outpatient), 4 (Other), 5 (Intermediate Care Facility I), 6 (Intermediate Care Facility II), 7 (Subacute Inpatient), 8 (Swing Bed), 9 (Reserved).
Third-digit frequency codes identify the bill's place in the episode: 0 (Nonpayment/Zero Claim), 1 (Admit Through Discharge — most common for closed inpatient episodes), 2 (Interim — First Claim), 3 (Interim — Continuing Claim), 4 (Interim — Last Claim), 5 (Late Charge), 6 (Reserved), 7 (Replacement of Prior Claim — adjustment), 8 (Void/Cancel of Prior Claim), 9 (Final Claim for Home Health).
Common TOB examples: 111 (Hospital Inpatient Part A, admit through discharge), 131 (Hospital Outpatient, admit through discharge), 721 (Clinic — Rural Health, admit through discharge). Misassignment of TOB is a common source of institutional claim denials. For example, a hospital outpatient service billed with TOB 111 (inpatient) rather than 131 (outpatient) will either deny or adjudicate under the wrong benefit.
For RCM operations, TOB assignment typically occurs at the patient accounting system based on admission status, discharge status, and bill timing. Automated TOB logic in the PM or HIS maps patient classifications to appropriate TOB codes. TOB errors tend to cluster around edge cases: patients admitted and discharged same day (observation vs. inpatient), patients requiring interim billing before discharge, patients with benefit changes during the stay, and bill adjustments requiring frequency code 7 or 8.
Denial and rejection patterns related to TOB include mismatch between TOB and other claim fields (e.g., outpatient TOB with inpatient-only revenue codes), incorrect frequency code on adjustments, and wrong facility type for the provider's Medicare provider number. Patient accounting teams should monitor TOB-related denial trends and coordinate with HIM and utilization management to address systemic TOB misassignment root causes. Automated TOB validation at claim scrubbing catches most errors before submission; manual TOB review is typically reserved for unusual billing scenarios where automated logic does not apply.
Industry benchmark
TOB structure: 3 digits (facility type, bill classification, frequency). Common values: 111, 131, 721. TOB errors: frequent cause of institutional claim rejections.
Worked example
A patient is admitted to the hospital for surgery and discharged three days later. The final claim uses TOB 111: first digit 1 (Hospital), second digit 1 (Inpatient Part A), third digit 1 (Admit Through Discharge). If the claim required amendment, a replacement claim would use TOB 117 (last digit 7 for replacement). If the patient had required interim billing mid-stay, the first interim claim would use TOB 112 and the final claim TOB 114.
Frequently asked questions — Type of Bill (UB-04 Form Locator 04)
What are the most common TOB codes?
111 (Hospital Inpatient Part A), 131 (Hospital Outpatient), 721 (Clinic — Rural Health Outpatient). Most provider types have a primary TOB for their primary service line.
What does the third digit mean?
Frequency code: 1 (admit through discharge), 2–4 (interim first/continuing/last), 5 (late charge), 7 (replacement — adjustment), 8 (void — cancellation).
How do I correct a TOB error?
For paid claims, submit a replacement claim with the correct TOB (third digit 7) that references the original claim number. For rejected claims, resubmit with correct TOB.
Disclaimer
This glossary entry is operational reference for revenue-cycle and medical-billing professionals. It is not legal, clinical, or contractual advice. Industry benchmarks cite named public sources where available; always verify against the current guidance from the authority body before relying on a number in a contract, policy, or compliance filing.