SAN DIEGO – To receive appropriate payment for Mohs surgery, using the correct codes is key.
While there are not many CPT codes for Mohs, it is crucial to use the right ones, and the right add-on codes, to get full payment for work and to avoid the headache of resubmission and third-payer arguments, Denise Harriman Koger said at a meeting sponsored by the American Society for Mohs Surgery.
One aspect of Mohs makes it unique among all other dermatologic surgeries, said Ms. Kroger, a billing specialist from San Diego. "You must act as both surgeon and pathologist for this, and if you don't, you are not doing Mohs, and you can’t use Mohs codes to bill. If either of these responsibilities is delegated to another physician who reports his services separately, these codes are not appropriate."
The money trail begins with clear documentation of why Mohs is the best treatment, she said. "You need to document this – whether it's an aggressive tumor, one with poorly defined margins – whatever it is. If you are subject to a post-review audit after submitting the claim, they will want to see your reasoning about why you chose Mohs rather than a simple excision."
CPT code 17311 is probably the "most-utilized code for stage I Mohs," she said. It covers procedures on the head, neck, hands, feet, genitals, or any other location that directly involves any of those areas – including muscle, cartilage, bone, tendon, major nerves, or blood vessels. "These are the areas where Mohs is most indicated, especially the face, because lesions on the face are where you want to preserve as much tissue as possible." This code covers up to five tissue blocks from stage I.
For every additional stage performed, use the 17312 code and bill it in units. "For example, if you do three more stages, you would bill 17312 times three," Ms. Koger said. Code 17312 is only used in conjunction with 17311. "That primary code is rarely billed in units unless you are doing two separate lesions. And a lot of insurance companies won't pay for two first stages on the same day." But if two separate lesions are addressed on the same day, continue to bill each one as a unit of the 17312 code.
Again, each additional stage is covered for up to five tissue blocks. Since 17312 is an add-on code, it is not subject to the multiple surgical reduction rules. "If your billing staff sees the payer reducing the fee on this code, they should appeal," Ms. Koger advised.
Code 17313 covers the first stage of Mohs surgery on the trunk, arms, or legs. Again, up to five tissue blocks are covered. The add-on code for additional stages is 17314, which should be billed in units and is not subject to the multiple surgical reduction rule.
"Sometimes you might get a lot of referred patients, who may or may not arrive with a biopsy slide and report," she said. "If you don’t have it, there are some rules as to whether you can bill for a biopsy and frozen section done on the same day as Mohs."
If a biopsy has been done in the previous 60 days and the surgeon has access to it, then no billing can be submitted for a same-day biopsy. "But if you've tried to get it and were not able to, document that and do another biopsy that day."
In order to get paid for that biopsy, however, the billing code modifier 59 is necessary. "This is very important because it's how you get paid for those same-day biopsies and frozen sections. If you bill 17311 without the 59 modifier [after a same-day biopsy] it will be denied because the payer will consider it bundled in."
If more than five tissue blocks are required for any stage, the billing code is 17315. This billing code should be listed separately in addition to the primary procedural code.
Three other important modifier codes are 58, 78 and 79, Ms. Koger said. Modifier 58 covers related procedures done by the same physician during the 90-day postoperative period, including major surgery. It also covers Mohs on a different site, or an incision or excision on the day of Mohs surgery.
If a patient needs to return for a related procedure to the operating room in an outpatient surgery center or hospital during the post-op period, code 78 is the one to use. "Modifier 79 is used if you are doing Mohs during the global period of a previous surgery; it tells the payer that the Mohs is unrelated to the prior work. You need to use that to tell them it’s unrelated to the work you did. For example, if you perform Mohs on the scalp and repair the defect and then 3 weeks later you excise a cyst somewhere else."