Part A to B Rebilling Guidance

When an inpatient admission is found to be not reasonable and necessary, payment is allowed for all hospital services furnished that would have been reasonable and necessary in an outpatient setting.

Hospitals may also be paid for Part B inpatient services if it's determined that a beneficiary should have received hospital outpatient services rather than inpatient services, and the patient has already been discharged from the hospital.

Note: Claims that are not affected by this billing are; Recovery Audit Contractor (RAC) pre-payment review claims, Supplemental Medical Review Contractor (SMRC) post-payment review claims denied for Intensive Inpatient Rehabilitation Therapy, and pre-payment denials based on contractor review for Bariatric Surgery.

Self-audit Claims

Submit a Part A provider liable claim with the below information on the UB-04 claim form.

  • Type of Bill (TOB) 110
  • Non-covered days
  • From and thru dates of service
  • Appropriate patient status
  • Occurrence Span Code M1 with dates of service
  • Non-covered charges
  • Diagnosis codes
  • Procedure codes

After the inpatient claim has finalized, an inpatient Part B ancillary claim (TOB 12x) can be submitted.

Inpatient Part B Hospital Services

Includes services that are not strictly provided in an outpatient setting. Medicare pays for certain non-physician medical services.

Non-covered Services at Revenue Code Level

A list of non-covered revenue codes can be viewed under CMS Internet Only Manual (IOM), Publication 100-04, Medicare Claims Processing Manual, Chapter 4, Section 240.1.

For admissions denied as not reasonable and necessary, submit a Part B inpatient ancillary claim (TOB 12x) containing:

  • Treatment authorization code: A/B Rebilling
  • Condition code W2
  • Original denied Document Control Number (DCN) in remarks
    • For Direct Data Entry (DDE) or paper claims, enter word "ABREBILL" and denied inpatient DCN in remarks field. Example: ABREBILL12345678901234

Outpatient Services Provided Prior to Admission

Includes outpatient diagnostic services furnished to patients three days prior and up to the date of admission.

Covered Diagnostic Revenue Codes

Revenue Code Description
0254 Drugs incident to other diagnostic services
0255 Drugs incident to radiology
030x Laboratory
031x Laboratory pathological
0341, 0343 Nuclear medicine, diagnostic/Diagnostic Radiopharmaceuticals
035x CT scan
0371 Anesthesia incident to Radiology
0372 Anesthesia incident to other diagnostic services
040x Other imaging services
046x Pulmonary function
0471 Audiology diagnostic
0481, 0489 Cardiology
0482 Cardiology, Stress test
0483 Cardiology, Echocardiology
053x Osteopathic services
061x MRT
062x Medical/surgical supplies, incident to radiology or other diagnostic services
073x EKG/ECG
074x EEG
0918 Testing, Behavioral Health
092x Other diagnostic services


Submit an outpatient Part B claim containing the below information on the UB-04 claim form.

  • Type of Bill (TOB) 13x
  • Applicable revenue codes/services



Last Updated Dec 09 , 2023