Modifier 59: When to Use It, NCCI Rules & Examples

Modifier 59 is used to indicate that components of a procedure that are normally reported together should be reported separately under specific circumstances. It is commonly associated with NCCI editing in medical billing, but use of Modifier 59 does not mean that the service will be paid separately.

It is important to determine whether there is a code pair edit, what the clinical situation is, and if the situation can be better described by another modifier.

Modifiers 59 are used to describe situations where there are clearly defined circumstances that warrant reporting of each individual service. Use of Modifier 59 should not be used to routinely “unbundle” services.

It is important to review the NCCI edit that is currently in effect.

If the report for the edit states a CCMI of 0, use of an NCCI exception modifier would not justify updating the edit.

Other modifiers that may more appropriately describe the situation are Modifiers XE, XP, XS, or XU.

Distinct clinical situations and appropriate documentation are essential to warrant reporting of procedures as separate services.

It is important to ensure that payer guidelines are reviewed in order to assess what services would be covered for Medicare, Medicaid, and private payors.

Modifier 59 Meaning in Medical Billing

Modifier 59 is used to define that a specific procedure is distinct from other services that may otherwise be grouped together. It is used to identify a procedure or service that is not normally reported and may not be combined with other procedures and/or services.

You may think of Modifier 59 as additional information that is transmitted with a procedure code.

When using Modifier 59, you are not requesting payment for a procedure.

You are explaining to the payer that while the procedures may be grouped or bundled, the situations in this case warrant that the procedures be performed and reported as individual or separate procedures.

It is important to understand the difference in communicating the use of a modifier and what the modifier is actually communicating.

A modifier cannot be used to justify medical necessity. It also cannot change the status of a service from non-covered to covered.

What Modifier 59 Actually Communicates

According to the circumstances of the case and the rules of coding, the distinction may require:

• A different date of service
• A different part of the body
• A different injury or wound
• A different part of a procedure
• A different service that is not connected to the other service

The record must support which distinction is applicable.

Merely reporting two CPT codes on the same date does not justify reporting two procedures on the same day.

Why Modifier 59 Is Closely Connected to NCCI Edits

Using Modifier 59 correctly requires an understanding of NCCI Procedure-to-Procedure edits.

NCCI PTP edits are created and updated by CMS to prohibit the inappropriate reporting of code combinations that should not be billed together.

Each PTP edit consists of two codes.

For example, code A in column one and code B in column two.

If code combinations A and B are reported on the same date for the same patient, code B will not be paid, unless an exception to the edit is allowed and the conditions warrant an NCCI modifier.

Understanding code bundling is essential for proper application of modifier 59.

If code B should not have been reported with code A, the proper code and modifier should be submitted and the bundling should be challenged.

However, the first question should not be, “Will modifier 59 allow code B to be reported?”

The first and foremost question should be, “Does the current NCCI bundling edit prevent reporting of codes A and B?”

CCMI 0, 1 and 9

Every NCCI PTP edit includes a Correct Coding Modifier Indicator, commonly abbreviated as CCMI.

A CCMI of 1 indicates you need to further evaluate your case, and does not allow you to automatically justify the use of Modifier 59.

You will need to provide supporting documentation and a legitimate reason for the denial to override the use of Modifier 59.

Date of Service Matters

Updates to the NCCI files occur on an ongoing basis.

The latest NCCI file version must always be used for the date of service in order to provide an accurate editing analysis.

Reliance on historical files, memos or spreadsheets is not permitted.

The edit status for a particular code pair may have changed since the historical analysis was performed.

Pre-bill review for NCCI editing is standard practice for experienced coders and coders-in-training. The purpose of this practice is to validate that no edits will be made to the claim.

When Modifier 59 May Be Appropriate

Modifier 59 may be reported in instances in which a legitimate coding edit exists for a separately performed service.

The following represents a few of the major situations that need to be considered.

Modifier 59 may be reported when the services were performed on separate body systems. For example, Modifier 59 may be reported on a second surgery code if the initial surgery involved the inner ear and the second surgery involved the middle ear.

Separate Anatomical Sites

Procedures that occur in different areas of the body can be reported as two separate procedures, even if they happen at the same time.

For example, if a clinician performs two procedures, one on each of a patient’s lesions, e.g. one on a lesion of the arm and one on a lesion of the leg, this is considered two separate procedures.

This is not the case if the procedure is performed on a single lesion and the procedure is divided into two or more component parts.

The location of each service performed must be documented.

”Procedure performed at separate site” is not an acceptable documentation.

Documentation should include the location and the procedure performed at that location.

For example, “Procedure X performed on the left arm” and “Procedure X performed on the left leg.”

Consider if the documentation would be clearer with the use of Modifier 59 instead of an anatomical modifier e.g. LT or RT.

Separate Encounters on the Same Date

It is possible for a patient to have more than one encounter in a service date, even if it happens to be scheduled back to back.

For instance, a patient may come in for a scheduled procedure in the morning, leave once that procedure is done, and come back for a separate, unscheduled procedure in the afternoon.

The details surrounding these situations may give a payer the justification to allow separate payments for the procedures.

Separations should be clear in the record: the time the first service ended, the reason for the patient’s return, the time the second service started, what was evaluated or treated, and what service was performed.

In general, two services performed during the same visit do not warrant a payment for two separate services. There must be a clear justification for a second service in order to support separate payment.

Separate Lesions or Injuries

The use of Modifier 59 may be allowed when treatment of different lesions or injuries is done via different procedures during the same visit. This happens often in the practices of Dermatology, Wound Care, and Surgical practices. Documentation is extremely important to clarify the services rendered and the reason for medical necessity for each service so that providers are reimbursed appropriately. If there is an inability to determine which lesion is being referred to when describing a procedure, then the documentation is considered insufficient. Providers using dermatology billing services should ensure that the location of each lesion and the procedural information is documented in order to clarify which lesion is being treated and to justify medical necessity for each service.

Separate Procedural Sessions

There may be times when different procedures happen on the same date but are coded as different sessions.

Using the time difference to determine whether procedures are done during a different session is not always correct. The record may show that the procedures were done during a different session but were of a clinical nature.

If there is a better modifier available that describes a separate procedure, it is advised to use that modifier instead of XE, especially if that is allowed by the payer.

Non-Overlapping Timed Services

Timed therapy services require specific consideration due to challenges with coding and documentation for overlapping minutes.

For the purposes of this example, let’s say there are two distinct time blocks, each containing a single timed service.

There are several pieces of information that may be documented concerning each service.

• The total number of minutes comprising the service.
• The number of units billed for the service.
• The service description.
• Any other necessary information to prevent inappropriate double counting of minutes.

The existence of two timed services, documented as occurring in the same time block, does not always mean the services were documented as occurring in the same time block.

For example, if two timed services are coded and documented as occurring on the same treatment day, this does not always mean the services occurred at the same point in time. It is possible the services spanned different points in time. Only a complete analysis of the entire service record would allow one to determine if inappropriate double counting of minutes occurred.

Five Checks Before You Append Modifier 59

A simple pre-bill sequence can prevent many errors.

1. Confirm the Code Pair

Check if the two CPT/ HCPCS codes have an active NCCI PTP edit for the date of service, and if so, for what setting.

If there is no bundling, then there is no need for a distinct-service modifier.

2. Review the CCMI

If the edit carries a 0, you can be sure there won’t be consideration of payment. In this case, you cannot justify with modifier 59 or any other NCCI-related modifier.

A code with an edit of 1 warrants more review to determine if it can be supported.

3. Identify What Makes the Services Distinct

Can you identify the pertinent reason?

Was it a different experience?

Is the structure different?

Is the lesion different?

Is the service different?

If you do not clearly identify the distinction, do not add a modifier.

Armed with the knowledge of what to look for and what the answers are likely to be, coders can determine which modifier to select. In absence of an definitive answer, coders should leave the modifier off.

4. Look for a More Specific Modifier

Check anatomical modifiers and XE, XP, XS or XU.

Although a pair of codes is bundled with modifier 59, it should not be the first choice for selecting this modifier.

5. Read the Actual Documentation

Do not code from assumptions.

Note should substantiate the distinction the modifier indicates on the claim.

If distinction indicated by modifier on claim is “separate structure”, and the documentation does not capture different structures, then the claim is in error prior to leaving the billing system.

When Modifier 59 Should NOT Be Used

Knowing when not to use Modifier 59 is just as valuable as knowing when it applies.

Do Not Use It Just to Get a Denied Line Paid

Just because a payer denies a claim does not mean the code assigned to the service on that claim was incorrect.

Understand why the service was bundled or denied.

Check:

NCCI edit

CCMI

documentation

Modifiers

Payer’s policy

If adding modifier 59 is determined to be appropriate, failure to include it could represent an unbundling of a correctly bundled service. If the service was incorrectly bundled, 59 should be added to the appropriate line.

Do Not Override a CCMI 0 Edit

An NCCI PTP associated modifier can be applied only if the CCMI is not 0.

This is an absolute constraint.

An indicator of 0 is not changed to an indicator of 1 with the presence of exception documentation.

Do Not Use 59 When the Services Are Integral

It may not be required to report procedures if reporting one requires reporting the other.

Although a provider may have performed both procedures, it does not mean each is reportable and billable separately.

There are coding rules and guidelines which determine how and what services are reported and not based on the number of services or the activities performed during a service.

Do Not Assume Different Diagnoses Are Enough

This error is very common.

Practices report one diagnosis with the first procedure and a different diagnosis with the second procedure and then assign Modifier 59 to both.

This does not apply Modifier 59 to both procedures.

Having different diagnoses may support the need for different procedures; however, different diagnoses do not allow for a distinct encounter, site, structure, lesion or service.

The determination of a distinct encounter, site, structure, lesion or service must be supported by other factors in addition to different diagnoses.

Do Not Use It When a More Specific Modifier Applies

Depending on the circumstances, the better modifier could be:

• RT
• LT
• Digit-specific modifiers
• XE
• XP
• XS
• XU
• Modifier 25
• Modifier 50
• Modifier 91

The correct choice depends on what actually happened and which modifier accurately communicates it.

Do Not Add It After the Fact to Repair Weak Documentation

A modifier cannot create information that was not recorded.

Modifiers must not be used to insert information that is not recorded. For example, if there is no supporting documentation that differentiates the provision of services, using Modifier 59 in an effort to deny payment would constitute an appeal error.

The original service must be fully and accurately documented in order for payment to be issued.

Modifier 59 vs XE, XP, XS and XU

CMS introduced the X{EPSU} modifiers to provide greater specificity about why services are distinct.

XE: Separate Encounter

Use XE when describing two distinct instances.

suppose a patient receives a service in the morning, leaves, comes back in the afternoon to receive a service, and leaves again.

in this case, there should be two distinct encounters documented on the patient’s chart.

XP: Separate Practitioner

According to XP, the service was performed by a practitioner other than the provider who signed the XP.

The identity of the person or persons who rendered each service must be disclosed.

It should not be presumed that XP has been correctly signed merely because more than one staff member was involved in an encounter.

XS: Separate Structure

XS may be used to describe a situation where the distinction is the presence or absence of an organ or other structure.

This may occur with various types of lesions, joints or anatomical regions.

Anatomical modifiers such as RT or LT may be more precise in some situations.

Prior to selecting XS, consult the payer- and code-specific rules.

XU: Unusual Non-Overlapping Service

Consider use of XU if you are describing a service that is distinct from the other services because it does not contain the ordinary aspects of a service, and it does not fit the description of XE, XP or XS.

Since evaluating and interpreting XU requires judgment, the documentation should support the case for non-overlap.

Where Modifier 59 Fits

Modifier 59 will still be useful in certain cases. However, it shouldn’t be the default answer to bundling edits. It should be considered as part of a larger thought process with other modifiers.

For example, if the payer requires specific anatomical modifiers and the request is justified, the thought process should be:

Specific anatomical modifier → X modifier when required by payer → Modifier 59 when appropriate.

These variations can occur for different payers. So it is important to confirm the payer’s specific requirements.

Modifier 59 vs Modifier 25

These modifiers solve different problems.

A simple rule to help you remember the essentials:

Modifier 25 is used in conjunction with an E/M code to denote the presence of a distinct medical problem and a procedure on the same date of service.

Modifier 59 is used to denote that two different procedures were performed on the same date of service that do not normally occur together.

Modifier 59 should not be used on an E/M code to deny payment. In this case, an E/M code Level 5 would be appropriate.

Modifier 59 vs Modifier 51

Modifier 51 is used when the same billing procedure is performed multiple times. Modifier 59 is used to identify procedures that are bundled together but should be reported separately.

They cannot be used interchangeably.

Modifier 59 cannot be used when two individual procedures are reported as part of a single service.

You must be able to document that a NCCI edit has been overridden in order to justify the use of Modifier 59.

Before you reach this conclusion, it is essential to examine the conditions and the circumstances of the case to validate that a NCCI edit has in fact been overridden.

Modifier 59 vs Modifier 50

Modifier 50 indicates that a procedure was performed on both sides of the body.

Modifier 59 indicates that a procedure was performed on a single side of the body, but that the side cannot be determined.

Performing a procedure on both sides of the body does not warrant the use of Modifier 59.

Some payers and CPT codes permit reporting of a procedure performed on both sides of the body by use of Modifier 50. Others may require reporting of a certain number of units, the left and right side procedures (RT/LT), or other methods.

It is always necessary to consult the payer and the CPT code in question to identify the method of reporting permitted.

Documentation That Supports Modifier 59

Documentation problems are the root cause of most modifier issues, and those issues ultimately result in paper-audit and/or billing issues.

A good note includes documentation to support why the modifier is appropriate. For example, instead of simply stating “59 applies,” the documentation should provide the reasons the services in question were not duplicative.

Documentation Checklist

Weak Documentation

Manual therapy and therapeutic exercise performed. Requested use of modifier 59.
Modifier 59 is used when two separate services are provided on the same date, but the services are unrelated.

Stronger Documentation Pattern

Manual therapy was performed on the area shown on the accompanying treatment record, for the period shown. Therapeutic exercises were performed to address a separate treatment goal, for a separate, non-overlapping period of time. The record shows the time and effort required to perform each service.
That, in and of itself, tells very little about the type or quality of the service provided. In the absence of the service details, the entry merely shows that the provider copied and pasted a commonplace modifier into the record.

AVOID COPY-PASTE MODIFIERS

The reports generated by this user often include multiple nearly identical phrases. This raises questions about the validity of the reports in general.

The report should document the details of the service the patient received.

Using the phrase “separate and distinct procedure” multiple times will not be useful in reporting what made the procedures distinct.

Practical Modifier 59 Billing Examples

While examples are important, they shouldn’t take the place of verifying the latest edit file.

Edits change. Rules change. Descriptor changes.

Consider these situations as examples of rule application as opposed to inflexible code-pair directorates.

Example 1: Physical Therapy

A therapist performs two services during distinct, non-overlapping treatment periods.

The coder should review:

• Whether the CPT pair has an active edit
• Whether separate reporting is permitted
• Treatment time
• Anatomical region
• Units
• Whether another modifier better describes the situation

The mistake is assuming that two therapy codes automatically justify 59.

They do not.

The treatment record has to show what makes them distinct.

Example 2: Dermatology

A dermatologist performs different procedures on two separately documented lesions at distinct anatomical locations.

The documentation should identify:

• Lesion A location
• Procedure performed on lesion A
• Lesion B location
• Procedure performed on lesion B
• Why each service was medically necessary

If separate structure is the basis for the distinction, XS or an appropriate anatomical modifier may be more descriptive than 59.

Example 3: Same-Day Return Encounter

A patient comes in for an appointment in the morning and an encounter is recorded.

The same patient comes back for a different issue later in the day.

A second, different procedure might create a NCCI edit conflict with the first service performed on the same day. In these cases, the coder would have to determine if the second visit indeed created a new, distinct encounter.

When a second, distinct, encounter is documented, XE may provide more detail than 59.

Example 4: Different Diagnoses, Same Site

A single physician performs two procedures at the same location, and assigns different diagnosis codes to each procedure.

In cases such as these, it is necessary to analyze the aspects of the services that determine whether or not they qualify as separate, distinct services.

Assigning different ICD-10-CM diagnosis codes does not in and of itself denote that the services were separately distinct.

Example 5: Two Procedures With No NCCI Conflict

Suppose there are no edits preventing bundling for the procedures, and the procedures are reportable separately.

Modifier 59 is not warranted, and may mislead, in this case.

Prior to selection of any modifier, the NCCI check should be performed.

Common Modifier 59 Mistakes

Mistake 1: Automatically Adding 59 After a Bundling Denial

This addresses the symptom and not the root of the issue.

Take a look at the remittance first.

Mistake 2: Failing to Consider the CCMI

When the CCMI equals 0, further discussion is not warranted.

Do not change the edit.

Mistake 3: Automatically Selecting 59

Edits should be specific and describe the reason for the edit as accurately as possible.

Mistake 4: Believing Two Diagnoses Mean Two Procedures

It is possible for two diagnoses to lead to the same procedure being performed.

Mistake 5: Not Properly Documenting the Case

Vague statements, such as “another area,” are not adequate.

Mistake 6: Scheduling Services Too Close Together

If the rules state that two separate services can be provided, they cannot be concurrent.

Mistake 7: Blind Trust in Billing Software

While billing software can assist in certain functions, it should not fully replace the clinical judgment of the user.

Edits and modifiers should be determined and supported by the user based on his/her/their clinical judgment and case documentation.

Where Should Modifier 59 Be Placed?

Modifier 59 is often thought of as something that always gets reported in column two. This idea should be clarified.

Most payers follow the national Correlated Medicare Contractor (NCMC) rules when establishing their own rules for edit process.

The safer approach is to:

• Recognize the pair of services under review.
• Read the NCCI rules that apply to the pair.
• Determine which service is less related to the other service.
• Review rules for anatomical edits to determine if an X modifier would be more appropriate.
• Review the rules for the payer to see where the modifier should be located and if there are any rules regarding modifier order.
• Lastly, verify the claim to ensure the edits were made correctly.

It is important to note, that CMS and payer guidelines should always take precedence over outdated medical billing services.

Modifier 59 and Medicare

To ensure appropriate coding, Medicare utilizes NCCI edits. NCCI edits can vary, and it is the responsibility of the coder to understand the edits pertinent to the date of service being coded.

If an NCCI edit is identified for the date of service being coded, and an NCCI modifier is permissible, the coder is to exercise judgment and determine if the modifier is appropriate.

It is important to remember the following rules concerning NCCI edits and modifiers:

An NCCI edit permitting a modifier does not ensure that the modifier is correct.

The final decision relies on the documentation and the judgement of the physician.

Edits can change throughout the year, therefore, during peak Medicare coding periods, practices should update the NCCI edits to ensure the accuracy of their coding.

Modifier 59 and Medicaid

Medicaid programs vary from state to state, and therefore require individual consideration.

Medicaid NCCI information is maintained by CMS, however State Medicaid agencies may have additional requirements.

Just because a modifier or code pair edit works within a Medicare environment, does not necessarily mean that same edit would function within a Medicaid environment.

Prior to submitting a claim for a Medicaid beneficiary, it is the responsibility of the provider to:

                     a. Verify the applicable Medicaid NCCI edits.
                     b. Verify state instructions and edits.
                     c.  Verify accepted modifiers.
                     d. Ensure edit documentation.
                     e. Verify and comply with State-specific billing requirements.

Commercial Payer Considerations

There are differences between various Commercial payer policies and Medicare policies.

Some Commercial payer policies may recognize the X modifiers, while others may have different coding edits, preferred modifiers, and claim processing requirements.

It is important to avoid designing your modifier workflow for a specific payer.

It is more effective to design a payer matrix which includes:

• Recognized modifiers
• The order in which modifiers can be used
• The documentation to be provided to support the use of modifiers
• Edits to codes
• What edits to codes require review and approval
• The deadline for filing appeals

This matrix should be regularly updated based on the changes made by the payers.

Modifier 59 Denials: A Practical Review Workflow

When a Modifier 59-related claim denies, resist the temptation to immediately rebill it.

Work through the denial methodically.

Step 1: Read the ERA or EOB

Identify:

• Denied line
• Group code
• CARC
• RARC
• Allowed amount
• Adjustment reason

The denial message tells you where to begin.

Step 2: Check the Code Pair

Confirm whether the codes have an active NCCI relationship for the date of service.

Step 3: Check the CCMI

Was a modifier even permitted?

If the answer is no, adding another modifier will not solve the underlying problem.

Step 4: Review the Original Documentation

Does it establish:

• Separate sites?
• Separate encounters?
• Separate practitioners?
• Non-overlapping services?
• Medical necessity?

Use the documentation that existed when the service was performed.

Step 5: Check Modifier Selection

Would XE, XP, XS, XU, RT, LT or another modifier better describe the circumstances?

Step 6: Review Payer Policy

NCCI eligibility does not guarantee that every payer processes the claim identically.

Step 7: Choose the Correct Action

The correct response may be:

• Corrected claim
• Reopening
• Appeal
• Documentation submission
• Accepting the bundling decision

Do not appeal a claim simply because the practice wants both lines paid.

Appeal when the coding, documentation and payer policy support the position.

Modifier 59 and CO-59 are not the same thing

There is very little difference here that leads to a great deal of misunderstanding.

Modifier 59 is used to identify different procedures, and can be used to combine multiple procedures into a single service.

On the other hand, CO-59 is used to notify the biller of the reason for a claim adjustment and should not be interpreteed as “Modifier 59 is missing.”

It is always important to review the entire explanation of review of the claim (ERA) to determine the reason for the edit, which includes the claim adjustment reason code (CARC) and the remittance advice response code (RARC).

Billing staff should not automatically add Modifier 59 to a code just because they see “59.” Doing so can simply confirm and extend a coding error.

A Better Pre-Bill Modifier Workflow

The best strategy for handling Modifier 59 is to prevent the denial on a post-payment claim basis. The ideal workflow looks like this:

• Always check your chart to confirm the accuracy of the documentation.
• Run code pairs against edit checks.
• Check the CCMI.
• Review the clinical scenario to determine the rationale for the clinical distinction.
• Check anatomical modifiers.
• Check XE, XP, XS and XU.
• Have a legitimate reason to support use of Modifier 59.
• Validate the appropriate use of time and units.
• Review and implement payer-specific edits.
• Run the claim through the final edits.
• Track claim denials.

The last step in the workflow is the most important step. If the reason for the denial is not resolved, do not indefinitely flag individual claims for additional review. This workflow may resolve the issue. If not, consider payer-specific training for the coding staff.

Quick Modifier 59 Decision Table

Frequently Asked Questions

What is Modifier 59 used for?

Modifier 59 identifies a distinct procedural service when procedures that are not normally reported together may be separately reportable because the documented circumstances make them distinct. It should not be added solely to bypass a bundling edit.

When should Modifier 59 be used?

It may be appropriate when an eligible NCCI edit exists, the services meet a recognized distinct-service circumstance, the documentation supports that distinction, and no more appropriate modifier describes the situation.

What is the difference between Modifier 25 and Modifier 59?

Modifier 25 applies to a significant, separately identifiable E/M service performed on the same date as another service or procedure. Modifier 59 addresses distinct procedural services. Modifier 25 goes on the E/M code; Modifier 59 applies to a procedure when appropriate.

Can Modifier 59 override any NCCI edit?

No. A CCMI of 0 means an NCCI PTP-associated modifier cannot bypass the edit. A CCMI of 1 means an override may be possible when the clinical circumstances and documentation support it.

Is Modifier 59 the same as XS?

No. XS specifically identifies a separate organ or structure. Modifier 59 is broader. When XS accurately describes the circumstances and is accepted under the applicable payer policy, it provides more specific information.

Do different diagnosis codes justify Modifier 59?

Not by themselves. Different diagnoses may support medical necessity, but the procedures still need to satisfy the applicable criteria for being distinct.

Does Modifier 59 guarantee reimbursement?

No. The modifier communicates why a service may qualify for separate adjudication. Coverage, medical necessity, NCCI rules, payer policy, documentation and contractual payment rules still apply.

Final Takeaway

In surgery and other similar cases, the decision to use Modifier 59 is typically made at the conclusion of the coding process. Because Modifier 59 indicates the services are otherwise unrelated, use of this modifier generally means that the documentation and the services rendered do not support the medical necessity of the claim being made.

Prior to submitting a claim, confirm the existing NCCI edit, review the CCMI, and determine what makes the services distinct. Claims should not be submitted until all of the documentation supports the services and there is a clear rationale to support the use of Modifier 59.

Using the above approach reduces the need to rely on Modifier 59 and improves both the claims and the documentation. In addition, this approach defends the overall billing process.