Dermatology Coding Alert

Knowing covered diagnoses is key, but don't be afraid to get a waiver.

If your dermatologist sometimes uses Unna boots to treat patients' lower extremities, you're probably familiar with code 29580, but you should know that the story doesn't necessarily end there. You may be missing out on coding for some associated procedures -- or wrongly coding for procedures that you shouldn't be.

Step 1: Identify the Covered Dx

As with any claim, you should support your Unna boot service (29580, Strapping; Unna boot) with a documented and applicable diagnosis.

Most payers will cover the procedure for a very limited number of diagnoses, including varicose veins of lower extremities (454.0-454.2) and lower limb ulcers, except decubitus (707.10, 707.12-707.19). Some payers will accept additional diagnoses, such as atherosclerosis of extremity with ulceration (440.23) or sprains and strains of the ankle and foot (845.00-845.19).

Best advice: Covered diagnoses for Unna boot applications vary greatly from insurer to insurer, so you'll have to look to your individual payer for guidance. Payers often update their policies on the different diagnoses. So, you'll want to check with them from time to time for any additional updates and information.

Step 2: Unsure of Coverage? Get a Waiver

If the dermatologist provides an Unna boot for indications or diagnoses that the payer does not approve (for instance, the physician may use an Unna boot as a burn dressing in some cases), you should ask the patient to sign a waiver. In the case of Medicare patients, use an advance beneficiary notice, or ABN.

Timing counts: You should ask for the waiver before providing the service. The waiver will make the patient aware that he -- rather than the insurer -- will be responsible for the cost of the service.

Step 3: Carefully Consider Reporting Additional E/M

In most cases, unless a separate and distinct service is performed other than CPT® 29580, you should not report an E/M service at the same time as an Unna boot application.

But if the patient has a new or different complaint that necessitates a separate and significant E/M service, you may report an appropriate E/M service (for example, 99213, Office or other outpatient visit for the evaluation and management of an established patient ...) appended with modifier 25 (Significant, separately identifiable evaluation and management service by the same physician on the same day of the procedure or other service).

Remember: Attach a separate diagnosis to the E/M service to further differentiate it from the "inherent" E/M service included in the Unna boot application.

Step 4: Recall the Rules for Debridement

Your dermatologist may frequently perform debridement prior to applying the Unna boot, but if both services apply to the same site, you should forget separate reporting. You can only report debridement (for example, 97597, Debridement [e.g., high pressure waterjet with/without suction, sharp selective debridement with scissors, scalpel and forceps], open wound, [e.g., fibrin, devitalized epidermis and/or dermis, exudate, debris, biofilm], including topical application[s], wound assessment, use of a whirlpool, when performed and instruction[s] for ongoing care, per session, total wound[s] surface area; first 20 sq cm or less]) during the same session as 29580 for separate anatomical areas (in other words, on separate feet).

The Correct Coding Initiative (CCI) bundles column 2 code 29580 into column 1 codes 97597-97598 as a standard of medical/surgical practice.

The edit does contain a modifier indicator of "1." If the physician performs a debridement on the patient's right foot and applies an Unna boot to the left foot, you may report both services with modifier 59 (Distinct procedural service) appended to 29580.

Step 5: Use 50 for Bilateral Boots

When medical necessity warrants, the surgeon may apply an Unna boot to each leg. In such cases, you should report 29580 appended with modifier 50 (Bilateral procedure), rather than billing for two separate units of 29580. Payers will reimburse 150 percent of the usual allowable amount.

Payer tip: Some payers request that you append modifier LT (Left side) or RT (Right side) to indicate which leg the surgeon treats when he applies the Unna boot to only one leg. Check with your individual insurer for guidelines.

Step 6: Include Supplies, Removal in Service

You should not bill separately for supplies when reporting 29580. Medicare and other payers will pay separately for casting and splinting supplies, but Unna boots don't fall into this category. Instead, payers include the cost of all Unna boot supplies (bandages, straps and paste) in their payment for 29580.

You cannot report a separate service for removing the Unna boot. Coders sometimes mistakenly report 29700 (Removal or bivalving; gauntlet, boot or body cast) for this service, but this is incorrect.