Procedure Coding: When to Use the Modifier 51
This is part of the Modifier Series, the articles include:
Modifier 51 is a modifier you probably use frequently if your provider performs surgical services. However, this particular modifier is exceptional in regards to where and how it should be appended. This is because for modifier 51, appropriate coding must take into consideration the RVU (relative value units) of the performed CPTs in order to be billed effectively. To put this into context and provide a clearer understanding of modifier 51, we’ll get started with explaining what exactly this modifier does, then discuss how and when to use modifier 51.
DEFINING MODIFIER 51
As mentioned earlier, modifier 51 is primarily put to work for physicians who bill surgical services. CPT guidelines explain the 51 modifier should apply when “multiple procedures, other than E/M services, are performed at the same session by the same individual. The additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s).”
In other words, modifier 51 reports that a physician performed two or more surgical services during one treatment session. The modifier would be applied to any secondary procedures performed. But with modifier 51, qualifications for the “primary” procedure code may be different from what you know about the use of other modifiers. To report the 51 modifier correctly, the coder should list the procedure with the highest RVU (highest paying) first, and use modifier 51 on the subsequent service(s) with lower RVU (lowest paying). Let’s get some clarification by reviewing examples of modifier 51 in use.
In order to better understand exactly when to use modifier 51, let’s take a look at some examples of modifier 51 correctly in use for multiple surgical procedures.
A dermatologist performs an excision of a malignant skin lesion. During the patient’s treatment, a separate skin lesion is discovered which the physician thinks warrants closer attention. After obtaining consent from the patient to perform a second procedure, the physician performs a biopsy of the new site. To bill correctly and appropriately, the coder would list the surgical services rendered as follows:
- 12031 (wound closure)
- 11600-51 (excision of malignant lesion
- 11100-51 (biopsy of skin, single lesion)
This is a good illustration of where our coding assumptions and the coding rules go their separate ways. Many billing and coding staff would think the excision should be indicated as the primary procedure, since it is the reason the patient obtained treatment. But with modifier 51 being dependent upon procedure cost, we find that the closure (highest cost) should be billed as primary, with the second and subsequent procedures of the excision and biopsy (lower cost) needing modifier 51.
An OBGYN’s patient is 10 weeks pregnant and schedules an appointment due to vaginal bleeding. After examination and ultrasound, the physician decides the patient is having a miscarriage and recommends immediate treatment. The patient also requests placement of an IUD. The OBGYN performs a surgical completion of the miscarriage and inserts the requested IUD during this visit.
Modifier 51 would be applicable in this scenario as follows:
- 58912 (incomplete abortion completed surgically)
- 58300-51 (insertion of IUD)
- 76817 (ultrasound)
A LESSENING NEED FOR MODIFIER 51
As with all matters of provider service billing, it is important that billing staff be proactive and stay informed about billing industry and payer standards. Learning and adapting to any changing necessity of modifiers will help the practice as a whole stay ahead of the billing curve. For instance, Medicare no longer requires modifier 51, as their internal systems are programmed to add 51 internally to the correct procedure code(s), and make the appropriate reductions to the remaining services billed. Many payers follow suit to the standards of Medicare, so it is evident that with modifier 51, knowing what payer requirements are in your area will be key to appending modifier 51 correctly avoiding unnecessarily denied claims.
Understanding correct and appropriate use of modifier 51 will be key to filing correct claims, which will then result in correct payment. Not only does the 51 modifier allow us to code physician services to the highest level of specificity possible, but it ensures the physician is paid accordingly for those services. However, it’s important to stay aware of the most current payer guidelines for appending modifiers, particularly modifier 51. Rules for applying the 51 modifier may vary depending on your state or locale, so it’s advisable to stay informed of any upcoming changes in payer requirements in order to maintain claims approvals and a healthy revenue flow for your practice.