Modifier A1

Dressing for one wound

Modifiers A1-A9 have been established to indicate that a particular item is being used as a primary or secondary dressing as well as to indicate the number of wounds on which that dressing is being used. If a dressing is not being used as a primary or secondary dressing on a surgical or debrided wound, the use of the A1-A9 modifiers would be inappropriate.

Dressings for surgical or debrided wounds must include one of the A1-A9 informational modifiers. The correct modifier to use is the number that corresponds to the number of wounds the dressing will be used for, NOT the number of wounds the beneficiary has.

Also be aware that it would be inappropriate to use these modifiers to identify the number of times the beneficiary is to be changing their dressings per day. The frequency of changes must be clearly indicated on the order based on the ordering physician's direction.


  • Gradient compression stockings/wraps (HCPCS A6531, A6532 and A6545)
    • These HCPCS should not be billed with A1-A9 modifiers when they are used for an open venous stasis ulcer

Appeal Option

Because the actual HCPCS codes require additional documentation and review, and are considered too complex, suppliers cannot submit a Reopening request for adding, changing or removing of the A1-A9 modifiers.

Such requests must be submitted via a Redetermination request.



Last Updated Wed, 02 May 2018 12:09:49 +0000