Ambulance claims submitted to Medicare require two-character origin and destination modifiers to identify where the patient was picked up and where the patient was transported. These modifiers are mandatory for most ambulance transportation services billed with HCPCS ambulance transport codes.
The letter E represents a Residential, Domiciliary, or Custodial Facility (other than an 1819 facility). It is not a standalone modifier and must always be paired with another origin or destination code, such as RE, ER, HE, or EH.
Correct use of Modifier E helps Medicare determine the patient’s transport route, supports accurate reimbursement, and ensures compliance with CMS ambulance billing requirements.
Modifier
E
Modifier Name
Residential, Domiciliary, or Custodial Facility (Other Than an 1819 Facility)
Plain English Explanation
The letter E tells Medicare:
“The patient was either picked up from or transported to a residential, domiciliary, or custodial care facility that is not classified as an 1819 facility.”
Purpose of Modifier E
Modifier E is used to:
- Identify residential or custodial care facilities involved in ambulance transports.
- Distinguish these facilities from hospitals, skilled nursing facilities, and patient residences.
- Report accurate ambulance origins and destinations.
- Support Medicare ambulance reimbursement.
- Ensure compliance with CMS origin/destination reporting requirements.
Understanding Modifier E
Ambulance modifiers always contain two letters.
- The first letter identifies the origin (pickup location).
- The second letter identifies the destination (drop-off location).
The letter E can appear in either position.
Examples include:
| Modifier | Meaning |
|---|---|
| RE | Residence → Residential/Domiciliary/Custodial Facility |
| ER | Residential/Domiciliary/Custodial Facility → Residence |
| HE | Hospital → Residential/Domiciliary/Custodial Facility |
| EH | Residential/Domiciliary/Custodial Facility → Hospital |
| NE | Skilled Nursing Facility → Residential/Domiciliary/Custodial Facility |
| EN | Residential/Domiciliary/Custodial Facility → Skilled Nursing Facility |
What Is a Residential, Domiciliary, or Custodial Facility?
Examples include:
- Assisted living facilities
- Adult foster care homes
- Group homes
- Personal care homes
- Residential care facilities
- Domiciliary care facilities
- Custodial care facilities
- Long-term residential care settings that are not classified as hospitals, skilled nursing facilities, or Medicare-certified 1819 facilities
When to Use Modifier E
Use Modifier E whenever:
- The ambulance transport begins or ends at a residential, domiciliary, or custodial care facility.
- The location is not a hospital, skilled nursing facility, physician’s office, or private residence.
- Medicare ambulance coverage requirements are met.
- A valid two-letter origin/destination modifier is reported.
When NOT to Use Modifier E
Do not use Modifier E when:
- The patient is transported to or from a hospital (H).
- The location is a skilled nursing facility (N).
- The patient is picked up from or transported to a private residence (R).
- The destination is a physician’s office (P).
- Modifier E is reported by itself.
Medicare Rules
CMS requires ambulance claims to include the correct origin and destination modifier combination.
Key Medicare rules include:
- Modifier E is never reported alone.
- The first letter identifies the pickup location.
- The second letter identifies the destination.
- The reported locations must match the ambulance run report.
- Incorrect modifier combinations may result in claim rejection or denial.
Always consult the current CMS Medicare Claims Processing Manual and Medicare Administrative Contractor (MAC) guidance.
Commercial Insurance Rules
Many commercial payers follow Medicare’s ambulance origin/destination coding structure.
However, commercial insurers may have:
- Different coverage policies.
- Different documentation requirements.
- Different reimbursement methodologies.
Always verify payer-specific ambulance billing requirements.
Documentation Requirements
Documentation should include:
- Pickup address.
- Destination address.
- Type of residential or custodial facility.
- Ambulance run report.
- Medical necessity for transport.
- Date and time of service.
- Mileage documentation.
- Patient assessment.
- Crew signatures.
- Receiving facility documentation, when applicable.
Real Billing Examples
Example 1 – Assisted Living to Hospital
A patient residing in an assisted living facility develops chest pain and is transported to the emergency department.
Billing
- HCPCS A0427
- Modifier EH
Example 2 – Hospital to Assisted Living Facility
Following treatment, the patient is discharged back to the assisted living facility by ambulance.
Billing
- HCPCS A0428
- Modifier HE
Example 3 – Residential Care Facility to Skilled Nursing Facility
A patient is transferred from a residential care facility to a skilled nursing facility.
Billing
- HCPCS A0428
- Modifier EN
Example 4 – Incorrect Use
A provider submits:
- A0428-E
This is incorrect because Modifier E cannot be reported by itself. A valid two-letter origin/destination modifier must be used.
CMS-1500 Claim Example
| Field | Example |
| HCPCS | A0428 |
| Modifier | EH |
| Diagnosis Pointer | Appropriate ICD-10-CM diagnosis |
| Mileage | A0425 (if applicable) |
Common Denial Reasons
- Modifier E billed alone.
- Invalid origin/destination modifier combination.
- Pickup or destination does not match documentation.
- Missing ambulance run sheet.
- Medical necessity not supported.
- Missing mileage documentation.
- Incorrect facility classification.
How to Correct the Denial
- Review the ambulance run report.
- Verify the pickup and destination locations.
- Confirm the facility type.
- Report the correct two-letter modifier.
- Correct and resubmit the claim if appropriate.
- Provide supporting documentation upon payer request.
Coding Tips
- Never report Modifier E by itself.
- Always pair E with another valid ambulance origin/destination code.
- Confirm whether the facility is a residential/custodial facility or a skilled nursing facility.
- Verify addresses before claim submission.
- Keep complete transport documentation.
Modifier E vs Modifier R
| Modifier | Description |
| E | Residential, domiciliary, or custodial facility |
| R | Patient’s private residence |
Modifier E vs Modifier N
| Modifier | Description |
| E | Residential, domiciliary, or custodial facility |
| N | Skilled Nursing Facility (SNF) |
Modifier E vs Modifier H
| Modifier | Description |
| E | Residential or custodial facility |
| H | Hospital |
Frequently Asked Questions (FAQs)
Q1. Can Modifier E be billed by itself?
Answer: No. Modifier E must always be combined with another origin or destination code.
Q2. What does Modifier E represent?
Answer: It represents a residential, domiciliary, or custodial care facility other than an 1819 facility.
Q3. What does EH mean?
Answer: EH indicates transport from a Residential/Domiciliary/Custodial Facility to a Hospital.
Q4. What does HE mean?
Answer: HE indicates transport from a Hospital to a Residential/Domiciliary/Custodial Facility.
AR Caller Tips
When following up on ambulance claim denials:
- Verify the pickup and destination addresses.
- Confirm that the facility type supports Modifier E.
- Review the ambulance run sheet.
- Ensure the correct two-letter modifier was billed.
- Verify medical necessity and mileage.
- Document the payer representative’s name, reference number, and appeal instructions.
Interview Questions
Question 1
What does Modifier E represent?
Answer: A residential, domiciliary, or custodial facility used in Medicare ambulance origin/destination coding.
Question 2
Can Modifier E be billed alone?
Answer: No. It must always be combined with another origin/destination code.
Question 3
What is the difference between Modifier E and Modifier R?
Answer: Modifier E represents a residential or custodial care facility, while Modifier R represents the patient’s private residence.
Practice Scenario
Scenario
A patient is transported by ambulance from an assisted living facility to the hospital emergency department because of shortness of breath.
Question
Which modifier should be reported?
Answer
The correct ambulance modifier is EH, indicating Residential/Domiciliary/Custodial Facility → Hospital.
Related Ambulance Modifiers
- D – Diagnostic or Therapeutic Site
- G – Hospital-Based ESRD Facility
- H – Hospital
- I – Transfer Site
- J – Freestanding ESRD Facility
- N – Skilled Nursing Facility
- P – Physician’s Office
- R – Residence
- S – Scene of Accident or Acute Event
- X – Intermediate Stop at Physician’s Office (Destination Only)
Common Billing Mistakes
- Reporting Modifier E as a standalone modifier.
- Confusing assisted living facilities with private residences.
- Confusing residential facilities with skilled nursing facilities.
- Using the wrong origin/destination sequence.
- Missing ambulance documentation.
- Incorrect mileage reporting.
Key Takeaways
- E represents a Residential, Domiciliary, or Custodial Facility.
- It is not a standalone modifier.
- It must always be reported as part of a valid two-letter ambulance origin/destination modifier.
- Accurate facility identification is essential for proper Medicare reimbursement.
- Thorough documentation helps prevent ambulance claim denials.
References
- CMS Medicare Claims Processing Manual, Chapter 15 – Ambulance Services.
- CMS Origin and Destination Codes for Ambulance Service Claims.
- Medicare Administrative Contractor (MAC) Ambulance Billing Guidance.
- HCPCS Level II Code Book.
Conclusion
The E ambulance origin/destination code identifies transports involving residential, domiciliary, or custodial care facilities. Proper use requires pairing E with another valid origin or destination code, accurate classification of the facility, and complete transport documentation. Following CMS ambulance billing requirements helps ensure compliant claim submission, appropriate reimbursement, and fewer denials.
Educational Disclaimer
This article was prepared with the assistance of artificial intelligence (AI) for educational and informational purposes. It is based on publicly available CMS guidance, Medicare ambulance billing principles, and general medical coding practices. It is not an official publication of CMS or the American Medical Association (AMA). Always consult the latest CMS Medicare Claims Processing Manual, HCPCS Level II codebook, Medicare Administrative Contractor (MAC) guidance, and payer-specific billing policies before coding, billing, or submitting claims.