Modifier 73
Modifier 73 = Discontinued outpatient hospital or ASC procedure before anesthesia. Learn when Modifier 73 applies, how it differs from Modifier 74, Modifier 53 and Modifier 52, what documentation supports the claim, how Medicare payment works and how AR callers can resolve Modifier 73 denials.
Modifier 73 at a Glance
The key points every medical biller, coder and AR caller should know.
Discontinued Procedure
Identifies a qualifying outpatient hospital or ASC procedure that was discontinued before anesthesia.
Facility Modifier
CMS describes Modifier 73 for facility reporting by outpatient hospitals and ambulatory surgical centers.
Before Anesthesia
The procedure is discontinued after the patient has been prepared and taken to the procedure room, but before anesthesia is administered.
Medicare Payment
CMS states that qualifying Modifier 73 procedures are paid at 50% of the full OPPS payment amount, subject to applicable payment rules.
What Is Modifier 73?
Understanding the modifier from the facility billing perspective.
Simple Definition
Modifier 73 is used by the facility to report a qualifying outpatient hospital or ASC procedure that was discontinued before anesthesia was administered.
Under Medicare guidance, the patient must have been prepared for the procedure and taken to the room where the procedure was going to be performed.
The procedure is then discontinued before anesthesia is administered because of extenuating circumstances or circumstances that threaten the patient’s well-being.
Easy Way to Remember
Think:
“73 = Procedure stopped before anesthesia.”
The patient has already been prepared and brought into the procedure room, but anesthesia has not yet been administered.
Important: Modifier 73 Is a Facility Reporting Modifier
CMS specifically describes Modifier 73 for reporting by the outpatient hospital department or ambulatory surgical center (ASC).
This distinction is important because Modifier 73 should not be treated as a generic modifier for every physician professional claim involving a discontinued procedure.
For professional physician services, different modifier rules may apply. Always verify the applicable CPT and payer guidance before reporting a discontinued-procedure modifier.
Where Does Modifier 73 Fit?
The timing of anesthesia is one of the most important factors.
Patient Prepared
Pre-procedure preparation is completed and the patient is taken to the procedure room.
Procedure Discontinued
The procedure is stopped before anesthesia is administered because of qualifying circumstances.
The Critical Point
Before anesthesia = Modifier 73.
If anesthesia has already been administered, Modifier 74 may be applicable instead.
When May Modifier 73 Be Appropriate?
Procedure Was Scheduled
A procedure requiring anesthesia was planned and scheduled.
Patient Was Prepared
The patient underwent the necessary preparation for the procedure.
Patient Entered Procedure Room
The patient was taken to the room where the procedure was intended to be performed.
No Anesthesia Yet
Anesthesia had not yet been administered when the procedure was discontinued.
Extenuating Circumstances
The procedure was terminated because of qualifying extenuating circumstances or circumstances threatening the patient’s well-being.
Facility Claim
The claim is being submitted by the applicable outpatient hospital or ASC facility.
When Should Modifier 73 NOT Be Used?
After Anesthesia
If the procedure is discontinued after anesthesia is administered, Modifier 74 may apply instead.
Physician Professional Claim
Do not automatically use Modifier 73 on a physician’s professional claim. Verify the applicable professional reporting rules.
Elective Cancellation
CMS states that elective cancellation of a procedure should not be reported using Modifier 73 or 74.
No Procedure Room
The basic circumstances must support the facility’s discontinued-procedure reporting requirements.
No Qualifying Circumstance
A simple change of plans does not automatically create Modifier 73 eligibility.
Anesthesia Already Given
Once anesthesia has been administered, the timing should be evaluated for Modifier 74 instead.
Modifier 73 vs Modifier 74
This is one of the most important distinctions in facility billing.
| Feature | Modifier 73 | Modifier 74 |
|---|---|---|
| Procedure Status | Discontinued | Discontinued |
| Anesthesia | Before anesthesia | After anesthesia |
| Patient Prepared | Yes | Yes |
| Procedure Room | Patient taken to procedure room | Procedure started or anesthesia administered |
| Facility | Outpatient hospital / ASC | Outpatient hospital / ASC |
| Medicare OPPS Payment | Generally 50% of full OPPS payment amount for qualifying cases | Subject to applicable OPPS payment rules; CMS generally does not apply the 50% reduction used for Modifier 73 |
| Memory Tip | 73 = Before anesthesia | 74 = After anesthesia |
Modifier 73 vs 52 vs 53 vs 74
Understanding the correct modifier prevents avoidable discontinued-service denials.
| Modifier | Basic Concept | Key Timing / Setting | Important Point |
|---|---|---|---|
| 52 | Reduced services | Generally physician/professional reporting | Used when a service is partially reduced or eliminated under applicable circumstances. |
| 53 | Discontinued physician service | Professional service context | Used for discontinuation of physician services under applicable CPT rules; CMS states it is not approved for outpatient hospital services. |
| 73 | Discontinued facility procedure | Before anesthesia | Outpatient hospital / ASC facility reporting. |
| 74 | Discontinued facility procedure | After anesthesia or after procedure started | Outpatient hospital / ASC facility reporting. |
What Counts as Anesthesia for This Medicare Rule?
CMS explains that for hospital outpatient reporting, anesthesia includes local anesthesia, regional blocks, moderate sedation/analgesia (“conscious sedation”), deep sedation/analgesia and general anesthesia.
Therefore, do not assume that “general anesthesia was not given” automatically means Modifier 73. The specific type and timing of anesthesia or sedation must be evaluated under the applicable Medicare guidance.
How Medicare Pays Modifier 73
Understanding the basic OPPS payment concept.
Patient Prepared
Facility resources are used to prepare the patient and the procedure area.
Procedure Discontinued
The procedure is stopped before anesthesia is administered because of qualifying circumstances.
OPPS Payment
CMS states qualifying procedures reported with Modifier 73 are paid at 50% of the full OPPS payment amount, subject to the applicable payment rules.
Payment Is Not the Same as “50% of the Billed Charge”
The Medicare rule refers to the full OPPS payment amount, not simply 50% of whatever amount the facility charged.
Actual claim payment can depend on the applicable Medicare payment system, status indicator, packaged services, APC and other payment rules.
Modifier 73 Documentation Checklist
Documentation should tell the story of exactly what happened.
Scheduled Procedure
Documentation identifies the planned procedure.
Patient Preparation
The record supports that the patient was prepared for the procedure.
Procedure Room
Documentation establishes that the patient was taken to the room where the procedure was intended to occur.
Reason for Cancellation
The record clearly explains why the procedure was discontinued.
Anesthesia Status
Documentation establishes that anesthesia had not been administered when the procedure was discontinued.
Clinical Record
Supporting medical-record documentation should be available for payer review.
Modifier 73 Examples
Educational examples showing how the timing changes the modifier.
A patient is prepared for a scheduled outpatient procedure and taken into the procedure room. Before anesthesia is administered, the patient’s condition changes and the procedure is discontinued.
CPT XXXXX-73If all applicable Medicare facility requirements are met, Modifier 73 may be appropriate.
The patient is prepared and anesthesia is administered. The procedure is then discontinued because of an unexpected clinical circumstance.
CPT XXXXX-74The timing points toward Modifier 74 rather than Modifier 73, subject to applicable payer rules.
The patient arrives for a procedure, but the facility and patient simply decide to reschedule for convenience.
Not automatically 73CMS states that elective cancellation should not be reported using Modifier 73 or 74.
A physician’s professional service is discontinued before completion.
Review 53 / CPT rulesDo not automatically apply facility Modifier 73 to the professional claim.
The procedure is cancelled while the patient is still in a pre-op area and has not been taken to the procedure room.
Review factsThe claim should be evaluated against the specific Medicare facility requirements rather than assuming Modifier 73.
Moderate sedation is administered before the procedure is discontinued.
Evaluate 74CMS includes moderate sedation/analgesia within its definition of anesthesia for this hospital outpatient reporting rule.
Common Modifier 73 Denials
Blue-only denial cards for AR and denial-management teams.
Modifier Not Supported
Documentation does not establish the circumstances required for Modifier 73.
Anesthesia Already Administered
The payer’s records indicate anesthesia or qualifying sedation was administered before discontinuation.
Wrong Modifier
The payer believes another discontinued-service modifier may apply.
Elective Cancellation
The procedure was cancelled electively rather than because of a qualifying circumstance.
Insufficient Documentation
The medical record does not clearly establish preparation, room entry, discontinuation timing or the reason for stopping.
Professional Claim Issue
Modifier 73 was applied to a professional service where the facility modifier rules do not apply.
Procedure Not Eligible
The billed service does not qualify for the applicable discontinued-procedure payment methodology.
Incorrect Facility Type
The claim does not meet the applicable outpatient hospital or ASC facility reporting requirements.
Payment Reduction Dispute
The facility expected full payment even though Modifier 73 triggered the applicable reduced OPPS payment methodology.
How an AR Caller Should Work a Modifier 73 Denial
Practical denial-management workflow.
Review the ERA / EOB
Identify the exact denial reason, CARC, RARC, claim line and adjustment amount.
Identify the Claim Type
Determine whether the claim is an outpatient hospital or ASC facility claim versus a professional claim.
Verify the CPT / HCPCS
Confirm the exact procedure code billed with Modifier 73.
Verify Procedure Timing
Determine whether the procedure was discontinued before or after anesthesia.
Verify Anesthesia / Sedation
Review the record to determine whether anesthesia, moderate sedation, deep sedation or another qualifying form had already been administered.
Review the Operative Record
Confirm patient preparation, procedure-room entry, discontinuation and the documented reason.
Check for Elective Cancellation
Determine whether the procedure was cancelled for a qualifying clinical circumstance or simply cancelled electively.
Compare Modifier 73 and 74
Before anesthesia generally points toward 73; after anesthesia points toward 74 under the applicable facility rules.
Correct or Appeal
If the modifier is incorrect, follow the payer’s corrected claim process. If it is correct and supported, submit reconsideration or appeal with the required records.
Document Follow-Up
Record payer representative, reference number, action taken, documents submitted and the next follow-up date.
AR Caller Script for Modifier 73
“I’m calling regarding a claim that was denied or reduced involving Modifier 73.”
“Could you please provide the exact denial reason and the applicable claim adjustment reason code?”
“Can you confirm whether the claim was processed as an outpatient hospital or ASC facility claim?”
“Can you confirm whether the denial is related to the Modifier 73, the procedure code or the documentation?”
“The procedure was discontinued before anesthesia was administered. Can you confirm whether your records indicate anesthesia or qualifying sedation was administered?”
“Can you confirm what documentation you require to support Modifier 73?”
“Does your policy require documentation showing that the patient was prepared and taken to the procedure room?”
“If the procedure meets your requirements, can we submit the operative report and supporting documentation for reconsideration?”
“Could you please provide the appeal or reconsideration submission method and the claim reference number?”
Modifier 73 Appeal Strategy
Identify the Denial
State the exact reason the payer denied or reduced the claim.
Establish Facility Type
Demonstrate that the claim is an applicable outpatient hospital or ASC facility claim.
Establish Timing
Show that the procedure was discontinued before anesthesia was administered.
Establish Preparation
Document that the patient was prepared and taken to the procedure room.
Explain Circumstance
Clearly document the clinical or extenuating circumstance responsible for discontinuation.
Request Reprocessing
Request reconsideration when the claim meets the applicable payer requirements.
Root Causes of Modifier 73 Denials
Wrong Modifier
Modifier 73 was used when Modifier 74 or another modifier may be appropriate.
Anesthesia Timing
Documentation shows anesthesia or qualifying sedation was administered before discontinuation.
Missing Documentation
The record does not establish the required preparation, procedure-room entry or reason for discontinuation.
Elective Cancellation
The procedure was cancelled electively rather than because of a qualifying circumstance.
How to Prevent Modifier 73 Denials
Verify Claim Type
Confirm that the service is being billed by an applicable outpatient hospital or ASC facility.
Verify Timing
Establish whether anesthesia was administered before discontinuation.
Document the Reason
Make the reason for discontinuation clear in the medical record.
Avoid Elective Use
Do not use Modifier 73 simply because a procedure was rescheduled or cancelled for convenience.
Review 73 vs 74
Build a front-end edit that checks anesthesia timing before submitting the claim.
Audit Denials
Track Modifier 73 denials by facility, CPT, payer and reason to identify recurring workflow issues.
Modifier 73 Decision Workflow
Use this before billing or appealing a claim.
Modifier 73 Quick Cheat Sheet
- Modifier 73 = discontinued outpatient hospital / ASC procedure before anesthesia.
- It is primarily a facility reporting modifier.
- The patient should have been prepared for the procedure.
- The patient should have been taken to the procedure room.
- The procedure must be discontinued before anesthesia is administered.
- CMS includes local anesthesia, regional blocks, moderate sedation, deep sedation and general anesthesia in its hospital-outpatient definition of anesthesia for this rule.
- The discontinuation should be due to qualifying extenuating circumstances or circumstances threatening the patient’s well-being.
- Elective cancellation should not be reported with Modifier 73.
- Modifier 74 generally applies when the qualifying discontinuation occurs after anesthesia or after the procedure has started.
- Modifier 53 is not the facility equivalent of Modifier 73.
- CMS states that Modifier 53 is not approved for outpatient hospital services.
- Medicare OPPS payment for qualifying Modifier 73 services is generally 50% of the full OPPS payment amount.
- Do not interpret 50% as 50% of the billed charge.
- Always verify the current payer-specific policy.
Modifier 73 and Medicare
Medicare Review Checklist
- Verify outpatient hospital or ASC facility status.
- Verify the scheduled procedure.
- Verify patient preparation.
- Verify procedure-room entry.
- Verify anesthesia timing.
- Verify reason for discontinuation.
- Verify that the cancellation was not merely elective.
- Review the applicable OPPS payment methodology.
CMS Guidance
CMS states that Modifier 73 is used by the facility when a procedure requiring anesthesia is terminated after the patient has been prepared and taken to the procedure room but before anesthesia is administered.
CMS created the modifier so facility costs associated with preparation, the procedure room and recovery resources can be recognized even though the procedure was discontinued.
CMS also states that qualifying Modifier 73 procedures are paid at 50% of the full OPPS payment amount.
Modifier 73 in an Ambulatory Surgical Center
Facility Preparation
The ASC prepares the patient and procedure environment.
Procedure Room
The patient is taken to the room where the procedure is scheduled to occur.
Procedure Discontinued
The procedure is stopped before anesthesia in a qualifying situation.
ASC Documentation Reminder
CMS compliance guidance states that ASC medical records should contain appropriate patient identification, informed consent, pre-surgical assessment and other relevant clinical and operative documentation.
For a Modifier 73 review, the record should clearly support the circumstances surrounding the discontinued procedure.
Modifier 73 and Medicaid
Medicaid Review
- Identify the state Medicaid program.
- Determine whether Modifier 73 is recognized.
- Verify facility billing requirements.
- Review the state fee schedule.
- Check Medicaid managed-care organization rules.
- Verify payment methodology.
- Review documentation requirements.
Important Medicaid Point
Medicaid reimbursement is not automatically identical to Medicare.
State Medicaid programs and Medicaid MCOs may establish different reporting, payment and documentation requirements.
Always verify the applicable state Medicaid or MCO policy before applying Medicare assumptions.
Modifier 73 and Commercial Insurance
Check Payer Policy
Confirm whether the commercial payer recognizes Modifier 73 for the facility claim type.
Verify Timing
Confirm whether the payer defines the anesthesia threshold the same way as Medicare.
Verify Payment
Do not assume the Medicare 50% OPPS methodology applies to a commercial payer.
CMS NCCI Reminder
CMS explains that NCCI promotes correct coding and helps prevent improper payment for services that should not be reported together.
Modifier 73 should not be appended merely to bypass an NCCI edit. The clinical and facility circumstances must actually support the modifier.
Always review the current NCCI policy and applicable Medicare Administrative Contractor guidance when a coding edit or denial is involved.
Modifier 73 FAQs
What is Modifier 73?
Modifier 73 is used by an outpatient hospital or ASC facility to report a qualifying procedure that was discontinued before anesthesia was administered.
What does Modifier 73 mean in medical billing?
It indicates that a planned facility procedure requiring anesthesia was discontinued after the patient had been prepared and taken to the procedure room, but before anesthesia was administered.
Is Modifier 73 for physicians or facilities?
CMS describes Modifier 73 as a facility reporting modifier for outpatient hospitals and ambulatory surgical centers.
What is the difference between Modifier 73 and 74?
Modifier 73 is used when the qualifying facility procedure is discontinued before anesthesia. Modifier 74 is used when the procedure is discontinued after anesthesia is administered or after the procedure has started, subject to the applicable rules.
Does Modifier 73 mean the procedure was completed?
No. Modifier 73 indicates that the procedure was discontinued and not completed.
Can Modifier 73 be used for an elective cancellation?
CMS states that elective cancellation of a procedure should not be reported using Modifier 73 or 74.
What happens if anesthesia was already administered?
The circumstances should be evaluated for Modifier 74 rather than Modifier 73 under the applicable facility reporting rules.
What counts as anesthesia for Modifier 73?
CMS’s hospital outpatient guidance includes local anesthesia, regional blocks, moderate sedation/analgesia, deep sedation/analgesia and general anesthesia.
Does Modifier 73 reduce Medicare payment?
CMS states that qualifying procedures reported with Modifier 73 are paid at 50% of the full OPPS payment amount, subject to applicable payment rules.
Is the 50% payment based on the billed charge?
No. The CMS rule refers to 50% of the full OPPS payment amount, not simply 50% of the facility’s billed charge.
Can Modifier 53 replace Modifier 73?
No. Modifier 53 and Modifier 73 have different reporting contexts. CMS states that Modifier 53 is used for discontinuation of physician services and is not approved for outpatient hospital services.
What documentation supports Modifier 73?
The record should support the planned procedure, patient preparation, movement to the procedure room, the reason for discontinuation and the fact that anesthesia had not been administered.
Can Modifier 73 be appealed?
If the claim meets the payer’s requirements and was incorrectly denied, the facility can follow the payer’s reconsideration or appeal process and submit the supporting documentation requested.
Is Modifier 73 used for ASC claims?
Yes. CMS specifically states that the instruction applies to both hospital outpatient departments and ambulatory surgical centers.
What should an AR caller check first?
Start with the ERA/EOB and identify the denial reason, claim type, CPT/HCPCS code, anesthesia timing, operative documentation and payer policy.
Is Modifier 73 the same as a reduced service?
No. Modifier 73 identifies a specific discontinued facility procedure circumstance. Modifier 52 represents reduced services under applicable reporting rules.
Before You Bill Modifier 73
- Confirm this is an outpatient hospital or ASC facility claim.
- Confirm the planned procedure required anesthesia.
- Confirm the patient was prepared.
- Confirm the patient was taken to the procedure room.
- Confirm anesthesia had NOT been administered.
- Confirm the procedure was discontinued because of qualifying circumstances.
- Confirm it was not merely an elective cancellation.
- Confirm the medical record supports the circumstances.
- Compare Modifier 73 with Modifier 74.
- Do not automatically use Modifier 73 on a professional claim.
- Verify current Medicare or payer payment rules.
- Keep documentation available for payer review.
Official CMS References
Use current CMS sources when validating Modifier 73, discontinued procedures and Medicare facility billing.
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