Introduction to Billing Procedures

Dermatologists perform many different procedures on a daily basis, so understanding the guidelines for proper billing and documentation of procedures is vitally important. Procedures are coded using the Current Procedural Terminology (CPT) guidelines. Within the field of dermatology, procedures are assigned global periods based on their level of complexity. A global period is defined as a length of time associated with a procedure, and its part of the global surgical package.

According to Centers for Medicare and Medicaid Services (CMS), the global surgical package includes: preoperative visit on the day before major surgeries or the day of minor surgeries, intraoperative services, postoperative care, supplies, wound care and postoperative complications.

Items that are not included in the global surgical package: the initial evaluation for surgery (major surgeries only) and unrelated procedures or office visits (with appropriate modifiers).

CMS provides a list of CPT procedure codes and their associated global periods ( For major surgeries with 90-day global periods, the actual number of days included in the global period is 92, because one must count the day before, day of surgery and 90 days following the surgery date. For minor surgeries with 10-day global periods, the actual number of included days is 11, counting the day of surgery and then the 10 days following. The majority of dermatology procedures will be either zero- or 10-day procedures.

Global periods have recently come under scrutiny by the federal government with legislation proposed to eliminate all global periods and require the physician to bill separately for postoperative follow-up visits in exchange for reducing the fee schedule of the CPT procedure codes. The American Academy of Dermatology has taken a stance against eliminating global surgical periods, and thus far no legislation has been passed to effectively eliminate the global period but providers should be aware the concept of global surgical periods may change in the future.

In many instances, the provider will need to make use of a modifier in order to justify billing codes and ensure proper reimbursement. A future article in this series will be devoted to modifiers, but it is important to note some of the most important modifiers related to performing procedures with global periods.

The 2 main modifiers providers should be aware of are the modifier “24” and the modifier “79.”

The “24” modifier is used to indicate a separate Evaluation and Management (E/M) encounter during a postoperative period of a prior performed procedure. For example, a patient who underwent Mohs with graft repair develops a rash 2 weeks later. The physician would need to use a “24” modifier to the office visit for the rash to indicate to insurance that this is a new and separate issue from the previous surgical procedure. If the same patient required a skin biopsy of the rash, the provider would need to use both “24” and “79” modifiers to indicate a separate office visit with a separate procedure from the graft repair. Proper use of the “24” modifier requires knowledge of the global periods associated with different dermatology procedures.

The “79” modifier is used to indicate the performance of a separate and unrelated procedure during a postoperative global period. This modifier is analogous to the “59” E/M modifier but indicates a new/separate procedure occurring during the global period rather than on the same date of service as the original procedure.

It is also important to note that CMS and many other carriers employ a multiple surgical procedure reduction rule. This applies to billing for multiple procedures performed during the same office visit. CMS states that it will reimburse 100% of the highest level submitted procedure, 50% of the second procedure and 25% of the third through fifth procedures.

Procedures with Zero-Day Global Periods

A few commonly performed procedures in dermatology are considered minor and have no global period attached to the CPT code (Table 1). This means that a patient who has a zero-day procedure performed would be eligible to receive additional reimbursable care by the same provider as soon as the next day, without the need for modifiers. All procedures discussed in this section have a zero-day global period.

Skin biopsies are common practice in dermatology, and are defined by CMS as a procedure used to confirm or establish a diagnosis. The associated CPT codes for skin biopsies are 11100 for the first biopsy, and 11101 for any additional biopsy performed during the visit. The 11101 code requires a number modifier to indicate how many additional biopsies were performed.

For example, if a patient has 3 skin biopsies on different sites during a clinic visit, the provider would submit a 11100 code and a 11101 code, with a “2” modifier to indicate 2 additional biopsies. These CPT codes apply to both punch and shave biopsies. Shave biopsies are different from shave removal procedures.

The CPT codes 11100 and 11101 include certain preoperative, operative and postoperative services. Included services are obtaining pertinent history about the lesion or eruption to undergo biopsy, discussion of risks and benefits of the biopsy, obtaining consent, examination of the area to undergo biopsy, the supplies needed to perform the procedure and postoperative care instructions and dressing supplies.

When performing multiple biopsies, it is important to clearly document the different lesions as being separate and using the appropriate multiple procedure modifier in order to be properly reimbursed. If multiple biopsies are performed of the same thing (ie, a rash), the specimen should go in 1 container and the provider should only code for 1 biopsy.

The provider should be aware that certain anatomic sites are considered special and therefore have different skin biopsy codes than the normal 11100 and 11101 series. These special sites and their associated CPT codes are listed in Table 2. These CPT codes usually reimburse at a higher level than the 11100 series. An easy way to remember these special sites is the phrase “See no evil, hear no evil, speak no evil, do no evil.” Recently, CMS changed the definition of eyelid biopsy to require involvement of the entire thickness of the eyelid margin. Therefore upper or lower eyelid skin that does not involve the lid margin, would be coded using the normal skin biopsy codes (Table 1).

Simple surgical repairs are repairs that do not include dermal sutures. A common example would be repair of a laceration using only external sutures or adhesive strips. Debridement of a laceration is included in a simple repair codes. The codes for simple repairs are 12001 to 12021 (Table 3).

The appropriate codes for simple closures follow the same guidelines as for intermediate closures, with the code based on the anatomic site and total closure length. Medicare is the only insurance carrier that requires an additional supply code (HCPCS code/G0168) when adhesive material is used to close a wound.

Surprisingly, Mohs surgery is considered a zero-day global procedure. Many Mohs procedures end up being associated with a 90-day global period due to the type of repair performed, but if a Mohs defect is repaired with second intention or simple repair, it will not have any postoperative global days.

Microscope procedures are commonly performed in dermatology and can be submitted for reimbursement. Scabies prep or potassium hydroxide exam of skin or hair can be documented using CPT code 87220, while microscopic examination of hairs plucked or clipped by the examiner to determine telogen and anagen counts, or structural hair shaft abnormality can be documented using CPT code 96920.

Unna boots are applied in the office and can be billed using CPT code 29580. A6456 is the supply code that should be submitted along with the CPT code, and if both legs receive Unna boots, the modifier-50 should be submitted to indicate a bilateral procedure.

Injection of Medications

These injections (not including intralesional injections) can be performed by a physician or nurse in the office, and therefore have associated CPT codes. If the patient is coming specifically for the injection, either the physician or the nurse can code for a 99211 office visit in addition to the injection CPT code. The CPT code for subcutaneous or intramuscular injection for therapeutic, prophylactic or diagnostic purposes is 96372. For methotrexate injections, there is a different CPT code 96401, which is for injection of chemotherapeutic agent. This CPT code reimburses at a higher level than 96372. Intralesional injections, associated with CPT codes 11900 and 11901, have assigned 10-day global periods and therefore are not included in this category.

The next article in this series will discuss in detail the dermatologic procedures associated with both 10-day and 90-day global periods.

Dr. Strowd is in practice in Reisterstown, MD.

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