Tests counted one by one, vials counted in doses
Allergy and immunology practices bill a mix of testing, long-term immunotherapy, office injections of biologic drugs and complex visits for asthma, food allergy and immune deficiency. Testing is billed by the number of individual tests, immunotherapy by the number of doses prepared and injections given, and Medicare counts doses differently from CPT. Small counting errors repeated over hundreds of patients add up quickly.
Allergy testing
| Test | Code | Units |
|---|---|---|
| Percutaneous (scratch, prick, puncture) tests | 95004 | Number of tests |
| Intradermal tests, sequential and incremental or immediate | 95024, 95027 | Number of tests |
| Patch tests | 95044 | Number of tests |
| Ingestion challenge (food or drug) | 95076, 95079 | Initial 120 minutes; each additional 60 minutes |
Positive and negative controls are not counted as tests. The interpretation is included in the testing codes, and an E/M visit on the same day is billed only when a separate evaluation is documented, with modifier 25.
Immunotherapy
- Injections: 95115 for one injection and 95117 for two or more at the same visit — never both.
- Antigen preparation: 95165 (multiple-dose vials) and 95145–95149 for stinging insect venoms are billed by the number of doses prepared, usually when the vials are made rather than when injected.
- Medicare pays only these component codes, not the complete-service codes 95120–95134, and has long defined a dose for 95165 as a 1 mL aliquot from the vial regardless of the amount injected. That definition has been under review, so the current physician fee schedule is checked each year.
- Commercial payers set their own dose definitions and limits on doses per year.
Biologics, asthma care and immunology
Biologic drugs for asthma, chronic urticaria, nasal polyps and eosinophilic disorders given in the office are billed with the drug’s HCPCS code and units plus an injection code, after prior authorization with documented severity and prior treatments. Spirometry and exhaled nitric oxide testing are billed with their own codes. Immunology practices that give immunoglobulin replacement bill infusion codes and the product by units, with strict authorization requirements. See prior authorization services.