On a regular basis, billers and coders confront a challenge when two procedures are performed on the same day for a patient. Can both procedures be submitted on a claim for reimbursement? Various limitations and restrictions apply, which make the answer not obvious. The potential for additional reimbursement creates a bias in favor of billing both codes — however, this may be an error and expose the practice to criticism. The Office of Inspector General of the Department of Health and Human Services has found that approximately 40% of such claims resulted in improper payments.¹

Separate procedure

CPT says, “Some of the procedures or services listed in the CPT codebook that are commonly carried out as an integral component of a total service or procedure have been identified by the inclusion of the term ‘separate procedure’. The codes designated as ‘separate procedure’ should not be reported in addition to the code for the total procedure or service of which it is considered an integral component.”² For example, 66030 is defined as “Injection anterior chamber of eye (separate procedure); medication.” During cataract surgery (66982 or 66984), it is common to inject medication into the eye during the procedure. Can 66030 and 66984 be billed together on the claim for reimbursement? The answer is no, because the injection of medication is an integral component of the cataract surgery. The “separate procedure” term in 66030 alerts the biller to consider this point.³

Further, CPT says, “However, when a procedure or service that is designated as a ‘separate procedure’ is carried out independently or considered to be unrelated or distinct from other procedures/services provided at the time, it may be reported by itself, or in addition to other procedures/services by appending modifier 59 to the specific ‘separate procedure’ code to indicate that the procedure is not considered to be a component of another procedure, but is distinct, independent procedure. This may represent a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injury).”

In our example, the injection of medication is not: a different session, a different surgery, a different site, a separate incision/excision, a separate lesion or a separate injury.^4,5

Consider another example. You perform cataract surgery on a diabetic patient. During the procedure, you also perform an intravitreal injection of an anti-VEGF agent for diabetic retinopathy. 67028 is defined as “Intravitreal injection of a pharmacologic agent (separate procedure)”. Can 67028 and 66984 be billed together on the claim for reimbursement? The answer is yes because the injection of the anti-VEGF agent is made through a different incision (pars plana) and in a different site (the posterior segment of the eye).⁶ It is noteworthy that billing software identifies 67028 and 66984 as bundled but may be unbundled under certain circumstances such as explained above.⁷

Medicare’s National Correct Coding Initiative

Variation in billing for the same service(s) occurs because the rules are complex and are interpreted differently by individuals with different skills and experiences. That also applies to different payers. Efforts to make payment policies and procedures uniform were adopted with the inauguration of the Medicare Physician Fee Schedule in 1992.

“The Centers for Medicare & Medicaid Services (CMS) developed the National Correct Coding Initiative (NCCI) program to promote national correct coding methodologies and to control improper coding that leads to inappropriate payment of Part B claims. The coding policies are based on coding conventions defined in the American Medical Association’s Current Procedural Terminology (CPT) Professional, national and local Medicare policies and edits, coding guidelines developed by national societies, standard medical and surgical practice, and/or current coding practice.”⁸

“The NCCI program includes three types of edits: NCCI Procedure-to-Procedure (PTP) edits, Medically Unlikely Edits (MUEs), and Add-on Code (AOC) Edits. NCCI PTP edits prevent inappropriate payment of services that should not be reported together. Each edit has a Column One and Column Two Healthcare Common Procedure Coding System (HCPCS)/Current Procedural Terminology (CPT) code. If a provider/supplier reports the 2 codes of an edit pair for the same beneficiary on the same date of service, the Column One code is eligible for payment, but the Column Two code is denied unless a clinically appropriate NCCI PTP-associated modifier is allowed and reported. MUEs prevent payment for an inappropriate number/quantity of the same service on a single day. An MUE for a HCPCS/CPT code is the maximum number of units of service (UOS) reported for a HCPCS/CPT code on the vast majority of appropriately reported claims by the same provider/supplier for the same beneficiary on the same date of service. Additional general information concerning NCCI PTP edits and MUEs is discussed in Chapter I. AOC edits consist of a listing of HCPCS and CPT Add-on Codes with their respective primary codes. An AOC is a HCPCS/CPT code that describes a service that, with rare exception, is performed in conjunction with another primary service by the same practitioner. An AOC is rarely eligible for payment if it is the only procedure reported by a practitioner.”

The NCCI edits are updated quarterly. Other third-party payers commonly use the NCCI edits but are not obligated to do so.

Modifier 59

Claims that involve separate procedures or bundled procedures require modifier 59 or X-modifiers (XE, XS, XP, XU).

CPT says, “Modifier 59 is used to identify procedures or services, other than E/M services, that are not normally reported together but are appropriate under the circumstances. Documentation must support a different session, different procedure or surgery, different site or organ system, separate incision or excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual.”

CPT also adds, “However, when another already established modifier is appropriate, it should be used rather than modifier 59. Only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. Note: Modifier 59 should not be appended to an E/M service.”

The reader should appreciate that X-modifiers are more specific than modifier 59. However, X-modifiers are part of HCPCS, and not part of CPT, so some clearinghouses and some payers may not recognize or accept them.

When are the X modifiers used?

The X-modifiers (ie, XE, XS, XP, XU) are used in situations where services are distinct and modifier 59 does not fully describe the distinction (Table). Some payers prefer them over modifier 59.

Here are some examples of X-modifier usage:

XE Separate Encounter. A service that is distinct because it occurred during a separate encounter (think E for encounter). A separate encounter involves a separate visit or session on the same day by the same provider or providers within the same group. Gonioscopy (92020) is defined in CPT as a “separate procedure”. If gonioscopy is performed in the morning in the clinic followed by laser trabeculoplasty in the afternoon at the ambulatory surgery center by the same physician, then it is billed as 92020-XE. It is noteworthy that billing software identifies 92020 and 65855 as bundled but may be unbundled under certain circumstances as in this case.

XS Separate Structure. A service that is distinct because it was performed on a separate organ/structure (think S for structure). Medicare defines a different anatomic site as one that
“…includes different organs or different lesions in the same organ. However, it does not include treatment of contiguous structures of the same organ. ... Treatment of posterior segment structures in the eye constitute a single anatomic site.”⁹ Different portions of the same retina or different areas of the same eyelid do not constitute a different structure. For example, NCCI edits bundle prophylaxis of retinal tear (67145) with retinal detachment repair (67108). When the prophylaxis and repair are performed in two different eyes by the same surgeon on the same day, then it is billed as 67145-XS. It is noteworthy that billing software identifies 67145 and 67108 as bundled but may be unbundled under certain circumstances as in this case.

XP Separate Practitioner. A service that is distinct because it was performed by a different practitioner (think P for practitioner). This applies when different providers in the same group are involved in the care of a single patient. For example, an optometrist performs extended ophthalmoscopy (92201) and identifies a retinal tear OS. Later the same day, an ophthalmologist in the same group practice lasers the retinal tear (67145-LT). The optometrist’s claim for extended ophthalmoscopy would read 92201-XP. It is noteworthy that billing software identifies 92201 and 67145 as bundled but may be unbundled 
under certain circumstances as in this case.

XU Unusual Non-overlapping Service. The use of a service that is distinct because it does not overlap usual components of the main service (think U for unusual). Use modifier XU for a diagnostic procedure that is performed before a therapeutic procedure when the diagnostic procedure is the basis for performing the therapeutic procedure.10 For example, you examine an infant with buphthalmos under general anesthesia (92018) and, based on that assessment, you made the decision to perform goniotomy (65820) later the same day for uncontrolled congenital glaucoma. Your claim for the EUA would read 92018-XU. It is noteworthy that billing software identifies 92018 and 65820 as bundled but may be unbundled under certain circumstances as in this case.

Now let’s consider a different example. You perform perimetry, optical coherence tomography (OCT) of the optic nerve, fundus photography (FP), and gonioscopy on a new patient with uncontrolled, moderate glaucoma, OU. NCCI bundles OCT and FP. This is not a separate encounter, structure, practitioner or an unusual, non-overlapping procedure. So, using modifier 59 or an X-modifier would not be appropriate. OCT and FP are only different images of the optic disc in glaucoma, so just one imaging service is reimbursed; the second one is incidental and bundled.

The concepts that support billing for two procedures on the same day that are otherwise bundled are subtle. The biller, coder, or physician should appreciate that they do not apply in every case but only in a minority of cases. Abuse of modifier 59 and X-modifiers have been identified by OIG and payers. Accurate billing ensures that health-care providers are reimbursed fairly for the services they provide, while maintaining compliance with coding standards. OM

References

1. DHHS OIG. Use of Modifier 59 to Bypass Medicare’s National Correct Coding Initiative Edits. November 2005. https://oig.hhs.gov/oei/reports/oei-03-02-00771.pdf. Accessed August 13, 2024
2. 2024 CPT Professional Edition, Surgery Guidelines, Separate Procedure 
3. Fletcher TA. Coding Separate Procedures: What Coders Need to Know MedLearn Publishing. February 26, 2019. https://tinyurl.com/43sr7wu3. Accessed August 13, 2024.
4. AAPC Knowledge Center. Quick Guide to “Separate Procedures”. August 2013. https://www.aapc.com/blog/25335-a-quick-guide-to-separate-procedures. Accessed July 31, 2024
5. AAPC Knowledge Center.“Separate Procedure Coding. January 19, 2015. https://www.aapc.com/blog/29062-separate-procedure-coding/. Accessed August 13, 2024.
6. Medicare Learning Network. Proper Use of Modifiers 59, XE, XP, XS, and XU. https://www.cms.gov/files/document/mln1783722-proper-use-modifiers-59-xe-xp-xs-and-xu.pdf. Accessed August 13, 2024.
7. CMS NCCI edits 
8. CMS. Medicare National Correct Coding Initiative Policy Manual. https://www.cms.gov/files/document/medicare-ncci-policy-
   manual-2024-introduction.pdf. Accessed August 13, 2024.
9. 2024 CPT Professional Edition, Appendix A – Modifiers. 
10. Medicare Learning Network. Proper Use of Modifiers 59, XE, XP, XS, and XU. https://www.cms.gov/files/document/mln1783722-proper-use-modifiers-59-xe-xp-xs-and-xu.pdf. Accessed August 13, 2024.