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.

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 been prepared in two separate vials.

The 1998 definition significantly reduced allergy treatment reimbursements for Medicare patients. This spurred the separate organizations representing otolaryngologists and general allergists to band together to convince HCFA to revert to its traditional definition, wherein the amount of allergen in each injection equals one dose.

The organizations argued that many patients on immunotherapy are allergic to several allergens and therefore require multiple vials and multiple shots. Furthermore, some allergens are not compatible with others (e.g., molds and pollens) and therefore need to be kept in separate vials.

In its November 2000 Final Rule, HCFA recognized that its 1998 definition was problematic and stated that as of Jan. 1, 2001, "physicians will be able to bill Medicare for each dose prepared in each multidose vial." Although this clarification should please allergy treatment providers, it is accompanied by three new guidelines that could complicate and diminish reimbursement for 95165:

1. HCFA clearly states that a maximum of 10 doses per vial should be billed, regardless of the size of the dose. For example, even if 20 0.5-cc doses are obtained from a 10-cc vial, only 10 doses should be billed.

2. HCFA categorically rejects additional billing for dilutions. According to the Final Rule, when a physician dilutes a multidose vial (for example, by taking a 1-cc aliquot from a multidose vial and mixing it with 9 cc of diluent in a new multidose vial), Medicare should not be billed an additional amount for these diluted doses. HCFA reasons, "The additional clinical staff and supply costs for preparing such a diluted vial are minimal, because allergens represent over 80 percent of the direct costs of preparing a multidose vial. In a diluted vial, there are no associated allergen costs, since they have already been billed in preparation of the initial vial."

Note: If fewer than 10 doses are prepared from a vial, the actual number should be billed. Otherwise, carriers may ask why the provider billed for 10 units of antigen but gave the patient fewer shots.

3. The clarification fixes a particular amount (1 cc) as a standard dose, stating that the practice expense inputs for 95165 "have been analyzed and adjusted so that they now correspond to the practice expense of preparing a 1-cc dose from a 10-cc (10-dose) vial," and concludes by stating that the Medicare Carriers Manual will be revised "to define a dose as a 1-cc aliquot from a single multidose vial."

This last requirement has been the most difficult component of the policy because allergy specialists frequently prepare 10 doses significantly smaller than 1 cc each. Many Medicare carriers have interpreted the clarification literally and will pay only for 1-cc doses as the billable unit, says Jami Lucas, executive director of the American Academy of Otolaryngic Allergy (AAOA). If the specialist prepares 10 0.5-cc doses, for example, Medicare will pay for five doses only.

Although the medical societies involved are working with HCFA to clarify this interpretation (and allow the provider to bill for 10 doses of 0.5 cc from a 5-cc vial, for example), the AAOA recommends allergy providers follow the guidelines laid out by their specific regional Medicare carrier.

The 1-cc definition of a dose has also complicated Medicare billing for providers who prepare doses off the board, says Teresa Thompson, CPC, an allergy coding and reimbursement specialist in Sequim, Wash. According to CPT, such services should be billed using codes 95120-95134, but -- because these codes are noncovered by Medicare -- most local carriers instruct providers to bill these services using 95165 and 95115 or 95117.

Because many off-the-board doses are less than 1 cc, uncertainty remains about whether 1 unit per dose of 95165 may be billed. In such situations, Thompson recommends billing for one unit only after 1 cc has been injected. For example, if the patient's dose is 0.5 cc, one unit of 95165 could be billed after two visits.

Slow and/or confused implementation of the HCFA guidelines outlined in the Final Rule further complicates this difficult issue. Although the clarification stated that HCFA planned "to issue new instructions to the carriers and update the carrier manual to ensure that appropriate payment is made as of Jan. 1, 2001," many carriers have yet to change their policies and still consider one dose to be whatever was injected into the patient during an immunotherapy session -- regardless of whether the patient received shots from one, two, or even three or more vials.

Many commercial carriers continue to pay for every dose administered to the patient if it is billed as a unit of 95165 (i.e., in accordance with pre-1998 Medicare guidelines). Because the majority of allergy patients are non-Medicare, however, physicians worry that private payers may adopt HCFA regulations, Thompson says. She adds that some carriers have already placed a limit on what they will pay per year for allergy treatment.

Private carriers often adopt beneficial HCFA policies, which gives additional urgency to efforts by allergy organizations to convince HCFA to modify those policies further and to return to the traditional definition of a dose. These efforts were aided by an April 2000 article in CPT Assistant that restated the definition of a dose as "the amount of antigen administered in a single injection from a multiple-dose vial." The volume of the dose is not mentioned and appears not to be a factor.

Given CPT's current policy, many private carriers are not expected to adopt the HCFA guidelines. The situation is far from settled: Although a further clarification from HCFA is anticipated, its contents are unknown at this time.