The professional service of preparation and provision of antigens for allergen immunotherapy — reported using CPT® 95165 Professional services for the supervision of preparation and provision of antigens for allergen immunotherapy; single or multiple antigens (specify number of doses) — is often misunderstood and incorrectly coded and billed to third-party payers. This misunderstanding causes a large compliance risk to any practice providing allergy services.

Consider the Components of Allergy Services

Allergy services are divided into three components:

1. Allergy testing
2. Professional service of preparation and provision of antigens for allergen immunotherapy
3. Administration of allergy immunotherapy (allergy shot(s))

Preparation and provision of antigens for allergen immunotherapy is performed once the patient has gone through allergy testing and it has been determined that the patient has allergies to one or more substances. The antigens for allergen immunotherapy are then prepared using the results of the allergy testing. The goal of the immunotherapy is to desensitize the patient to the elements to which the patient is allergic. The desensitization process involves administering very diluted antigens via injection, gradually building up to a maintenance dose over time.

Dosage Preparation Factors into Payment

The doses leading to the maintenance dose are all diluted by a significant amount of sterile saline. Dosage vials are initially prepared with maintenance doses of the antigens. A small amount of the maintenance dilution is placed into another vial. That vial is then filled to capacity (e.g., 10 cc) with diluent. This vial will have a different color top from the maintenance vial. A small amount of the diluted antigen from the second vial is withdrawn and placed in a third vial, which is also filled to capacity with diluent.

There are examples where some allergy preparations will continue this progression until seven vials, or 70 cc, of maintenance and diluted antigens are prepared.

The description in the CPT® code that describes this process says to “specify number of doses.” This means that you need to know how much antigen and diluent is drawn up into the syringe to make up a “dose.” You also need to know what the payer defines as a dose, as they may override the actual dose that is administered for a “reimbursable dose” definition specific to that payer.

Medicare Part B Has Its Own Rules

Medicare Part B has a very specific and restrictive definition of a “dose” for CPT 95165. No other payer (that I know of) has this same definition, stating in the 2001 Medicare Physician Fee Schedule final rule that a “dose” is 1 cc aliquot of maintenance antigen. Medicare Part B will not pay for diluent beyond what is needed to create the maintenance antigen.

2001 MPFS final rule

In the above example, where the three vials were created, two vials diluted from a maintenance vial, giving 30 cc of antigen, Medicare Part B would only pay for the original vial of non-diluted maintenance antigen — 10 units for the 10 cc in that vial.

Even if the patient is receiving 0.5 cc shots, meaning each vial provides 20 allergy shots, Medicare Part B only recognizes 1 cc doses. As a result, only 10 units may be billed to Medicare Part B. In the example above, where allergy operations make up seven vials, or 70 cc of antigen, you can only bill Medicare Part B for 10 units for the one maintenance dose vial.

Consider Unlikely Scenarios

Medicare Part B has medically unlikely edit (MUE) of any amount above 30 units to recognize that different vials of maintenance antigens can be made up for antigens that cannot be mixed together and must be kept separate. A patient who was given 30 units of 95165 received three shots. A patient who received 20 units of 95165 was given two shots.

DO NOT bill Medicare Part B for 20 or 30 units of diluted vials. The 20 or 30 units should only be billed to Medicare Part B if the patient has allergies such that the antigens cannot be mixed and must be kept separate in two vials (20 units) or three vials (30 units).