Otolaryngology Coding Alert

Providers who mix more than one vial of antigen may now bill Medicare for the total number of doses in all vials, as long as that number does not exceed 10 per vial, according to a clarification by HCFA (now the Centers for Medicare and Medicaid Services, or CMS) in the Nov. 1, 2000, Federal Register. The clarification was necessary, the document states, to resolve "the ambiguity and confusion in the medical community surrounding this issue."

But uncertainty about how to bill Medicare for 95165 (professional services for the supervision and provision of antigens for allergen immunotherapy; single or multiple antigens [specify number of doses]) continues, in part because many Medicare carriers have yet to implement the new guidelines -- and also because other billing problems involving this service remain unresolved.

Code 95165 describes the preparation of antigens prior to administration. Doses of single or multiple antigens are prepared either in vials or "off the board" (i.e., individual doses are prepared for patients when they arrive for their shot). Prepared vials usually include multiple doses.  

For example, the provider determines that a patient requires a series of 10 1-cc doses and prepares a 10-cc vial. During the same visit, he or she injects the first dose. Code 95115 (professional services for allergen immunotherapy not including provision of allergenic extracts; single injection) is billed for the injection and 95165 is also reported, with a "10" in the units box to indicate that 10 doses were prepared. For the remaining nine injections, only 95115 would be coded. For off-the-board antigen preparation, 95115 is billed along with one unit only of 95165.
Billing Multiple Doses Allowable
Some antigens cannot be mixed together in a single dose, which means the provider must prepare two or more separate doses. For example, if the patient requires immunotherapy for allergies to mold and pollen, separate vials need to be prepared and the patient will receive two injections.

The injections for the multiple doses are billed using 95117 (professional services for allergen immunotherapy not including provision of allergenic extracts; two or more injections). But billing 95165 for antigen preparation (in particular, determining the correct number of units) has been a major problem since May 1998, when HCFA modified its guidelines for allergen immunotherapy and, in doing so, defined a dose (95165) as "the total amount of antigen to be administered to a patient during one treatment session, whether mixed or in separate vials" [emphasis added].

The change had drastic payment implications for allergy providers: Regardless of the number of vials prepared or injections performed during a single session, only one dose could be billed. For example, the provider could bill only 10 units of 95165 even though 20 1-cc doses had [...]