Podiatry Coding & Billing Alert

Question: I’m trying to determine the correct ICD-10-CM code to establish medical necessity for a skin graft to a large pressure ulcer of the left ankle. There’s no staging documented by the provider in the notes during performance of the graft. When entering a diagnosis code to justify this procedure, should I code the pressure ulcer as unspecified based on the initial state of the wound, or should I code it unstageable due to its status after the procedure?

North Carolina Subscriber

Answer: According to ICD-10-CM guideline 1.C.12.a.1.2.3, unstageable wounds occur when you can’t assess and determine the depth of a wound, especially when the wound has produced eschar or after the wound has been covered by a skin graft. An unspecified wound occurs when the stage has not been documented, whether the depth can be determined or not.

In a case where a provider has performed a skin graft, the depth of the decubitus ulcer can no longer be assessed after the procedure, even by the podiatrist. You would classify the decubitus ulcer by its current stage after the skin graft, which is unstageable, L89.520 (Pressure ulcer of left ankle, unstageable).

However, to justify the CPT^® procedure code, the diagnosis code should indicate the pressure ulcer stage before the skin graft, hence the need for coding specificity. If you can, clarify the stage directly with the physician who needs to clarify with added documentation, or through previous notes if possible. If you’re unable to do that, you’ll have to code L89.529 (Pressure ulcer of left ankle, unspecified stage).