42 CFR §410.68

1. (a)Antigens that are furnished as services incident to a physician's professional services; or
2. (b)A supply of antigen sufficient for not more than 12 months that is—
   1. (1)Prepared for a patient by a doctor of medicine or osteopathy who has examined the patient and developed a plan of treatment including dosage levels; and
   2. (2)Administered—
      1. (i)In accord with the plan of treatment developed by the doctor of medicine or osteopathy who prepared the antigen; and
      2. (ii)By a doctor of medicine or osteopathy or by a properly instructed person under the supervision of a doctor of medicine or osteopathy.