Hopefully this will help:
Subject Ask Margie: Coding Unna boot application
Source Coder Pink Sheets: Orthopedic
Publication Orthopedic: Orthopedic Coder's Pink Sheet, October 2009, Vol. 10, No. 10
Effective Date Oct 1, 2009
Publish Date Oct 1, 2009
Question: We have noticed there is both a CPT® and a HCPCS code for Unna boots. The manufacturer is giving out the A-code for this service. What is the correct way to code these procedures?
Answer: It's easy to get confused about Unna boots, because they are different from most other casting procedures, which allow you to bill separately for casting supplies. With Unna boots, all supplies and services are included in a single CPT® code: 29580, strapping, Unna boot ($47.25 in the office, par, not adjusted for locality). That means it would never be appropriate to also report the A-code for Unna boot supplies.
You'll also want to make note of other services sometimes performed at the same time as an Unna boot, which may or may not be separately billable. For example, an E/M service may only be reported separately for an unrelated problem or separately identifiable service. Follow-up visits for an Unna boot typically are not billable.
In contrast, when debridements are performed in conjunction with Unna boot applications and re-applications, code the debridements instead of the Unna boot application.
Related E/M services are included: Unna boot treatments are scheduled in advance, and any E/M service related to the Unna boot and the wound is included. Like most procedures, Unna boot strapping includes a pre-procedure evaluation and routine follow-up care.
What it is: An Unna boot is a layered bandage filled with Unna paste and placed on a leg ulcer - which may be caused by increased venous pressure, venous insufficiency or capillary dysfunction. An Unna boot also may be placed to manage lymphatic edema, and also for sprains, strains, minor fractures, or as a protective bandage for burn grafts. The pressure from the bandage, which becomes semi-rigid, combined with the medication it contains, speeds the healing process. The process requires multiple treatments that can occur weekly or more often.
Initial assessment, unrelated visits need modifier 25: Medicare assigns 29580 "0" global days. That meansyou may report an E/M service for the initial assessment of the condition that prompted the decision to apply the Unna boot, as long as the assessment is significant and separately identifiable.
If the surgeon does a workup to identify the source and basis of the problem and then treats the problem, it's a significant, separately identifiable E/M service you can report with modifier 25 (significant, separately identifiable evaluation and management service by the same physician on the same day of the procedure or other service).
But if the patient comes in and the surgeon says, "yes, that's nasty, I think you need a Unna boot," it doesn't qualify for a separate E/M, and neither do follow-up visits.
If the patient comes for a scheduled treatment and has an unrelated problem, you can also report the appropriate established patient visit code with modifier 25. The unrelated diagnosis code (i.e., other than the diagnosis that led to the Unna boot treatment) should be linked to the E/M code.
Approved Unna Boot diagnoses: Unna boot treatments are covered for specific conditions only. Although carriers may vary greatly in the number of published diagnoses that support Unna boot application, most will accept the following indications and diagnoses: varicose veins of lower extremities; venous insufficiency, unspecified; chronic ulcer of skin; decubitus ulcer of lower extremity; ulcer of lower limbs; and edema of lower extremities.
Most - though not all - carriers explicitly do not cover Unna boot applications for sprains, strains or small fractures because other treatments, such as elastic bandage or taping, are just as effective clinically and cost less. To be certain when billing specific carriers, obtain their medical review policies or at least a list of approved diagnosis codes (preferably in writing).
Official resources:
CPT Assistant®, June 2005
~Kirsten, CPC