- Allergy immunotherapy CPT codes split into administration (95115, 95117) and antigen preparation (95165) - separate, separately billable services.
- 95115 = single injection; 95117 = two or more injections. Bill one or the other per date of service, not both.
- 95165 is billed per dose, where Medicare defines a dose as a 1 cc aliquot from a multidose vial, and caps billing at 10 doses per vial.
- Medicare assigns a Medically Unlikely Edit (MUE) of 30 units per day for 95165 - unit/dose miscounts are a top denial.
- A same-day E/M visit with an injection requires modifier 25 on the E/M, and only for a significant, separately identifiable service.
The allergy immunotherapy CPT codes trip up billers because they describe two different services that often happen at the same encounter: administering the allergy shot and preparing the antigen extract. Get the relationship wrong - or, more commonly, miscount the 95165 dose units - and you lose reimbursement on one of the highest-volume services in an allergy practice.
Allergy immunotherapy CPT codes at a glance
The first principle: antigen preparation and injection are separate services. When an allergist both prepares the extract and administers it, both can be reported. When a patient supplies serum prepared elsewhere, only the injection codes apply.
| Code | Description | Unit basis | Common denial |
|---|---|---|---|
| 95115 | Allergen immunotherapy; single injection (no antigen provided) | 1 unit per date | Billed with 95117 same day |
| 95117 | Allergen immunotherapy; 2 or more injections (no antigen provided) | 1 unit per date | Billed as 2 units instead of 1 |
| 95165 | Professional services for antigen prep, multiple-dose vials | Per dose (1 cc aliquot); Medicare max 10/vial | Unit/dose miscount; over MUE of 30/day |
| 95144 | Antigen prep, single-dose vials | Per single-dose vial | Billed when multidose vial used |
| 95004 | Percutaneous (scratch) allergy tests | Per test (per allergen) | Units don't match allergens tested |
95115 and 95117: the injection codes
These cover administering the shot when the antigen is not provided by the billing physician (the patient or another office supplied the serum).
- 95115 - a single injection. Report one unit.
- 95117 - two or more injections. Report one unit (not two or three).
- Never bill 95115 and 95117 on the same date - choose the one that matches the encounter.
The most common error is billing 95117 with multiple units. The code already accounts for two or more, so the unit count is always one.
95165 units and the Medicare 10-dose cap
95165 is the professional service for preparing and supervising antigens in a multiple-dose vial, and it is the code most likely to be denied for unit errors. Per CMS, a dose is a 1 cc aliquot from a single multidose vial. The practice-expense inputs assume ten doses per 10 cc vial, so Medicare allows a maximum of 10 doses (units) per vial, even if more than ten preparations are drawn.
| Scenario | Correct 95165 billing | Pitfall to avoid |
|---|---|---|
| One 10 cc multidose maintenance vial | 10 units (doses) | Billing 12+ because more aliquots were drawn |
| Diluted vials from the same antigen | Still capped at 10 doses per vial under Medicare | Billing each diluted prep past the cap |
| Two separate medically necessary vials | Up to 10 doses each, with documentation | No documentation of medical necessity for the second vial |
| Day exceeds 30 units | Hits the Medicare MUE of 30/day - requires justification | Submitting 30+ units with no supporting record |
If more than one multidose vial is medically necessary, you may bill additional vials - but document the medical necessity. Note that Medicare's per-vial dose definition can differ from some commercial payers; always confirm the specific payer's dose methodology.
Modifier 25: billing an E/M the same day as the injection
Allergy injections are minor procedures with their own work value. If the physician also performs a significant, separately identifiable E/M service on the same day - not just the routine pre-injection check - append modifier 25 to the E/M code. Routine pre-injection assessment is bundled and does not justify a separate E/M.
Common allergy immunotherapy denials and fixes
| Denial / problem | Root cause | Fix |
|---|---|---|
| 95165 units denied or downcoded | Dose count exceeds Medicare 10-per-vial cap or 30/day MUE | Recount doses as 1 cc aliquots, cap at 10/vial; document necessity for additional vials |
| 95115 and 95117 both denied | Both billed on the same date | Bill only one administration code per date |
| 95117 paid at single-injection rate | Billed as multiple units | Report 95117 as one unit; it already covers two or more injections |
| Same-day E/M denied as bundled | Missing or unsupported modifier 25 | Append modifier 25 only when a significant, separate E/M is documented |
| Injection-only claim denied for antigen | Patient supplied serum but prep code was billed | Use 95115/95117 only; do not bill 95165 when you did not prepare the antigen |
Frequently asked questions
95115 is the professional service for a single allergen immunotherapy injection, and 95117 is for two or more injections on the same date. Both are reported when the billing physician does not provide the antigen. Bill one unit of whichever code applies, and never report both on the same date of service.
Medicare defines a 95165 dose as a 1 cc aliquot from a multidose vial and caps billing at 10 doses (units) per vial, even when more than ten preparations are drawn. A standard 10 cc maintenance vial is therefore billed as 10 units. Medicare also applies an MUE of 30 units per day.
Yes, but only when the physician performs a significant, separately identifiable E/M service beyond the routine pre-injection check. Append modifier 25 to the E/M code and document a distinct problem, exam, and decision-making.
Antigen preparation codes (95165 for multidose vials, 95144 for single-dose vials) cover preparing and supervising the extract. Injection codes (95115, 95117) cover administering the shot. Bill both when you prepare and inject, but only the injection codes when the patient supplies the serum.
The most common cause is exceeding Medicare's 10-dose-per-vial cap or the 30-units-per-day MUE. Recount doses as 1 cc aliquots, cap each vial at 10, and document medical necessity if more than one vial is required. Commercial payers may count doses differently.