Specialty Billing Published July 20, 2026 · Yagnesh Dave

Allergy & Immunology Billing: 2026 Guide

Allergy and immunology practices have a billing profile that's unlike most specialties. You're often running allergy testing, mixing and administering immunotherapy, and managing complex patients across multiple visits — each with its own documentation and coding requirements.

If you're working through these issues, our specialty billing services can help you address them systematically.

Allergy Testing Codes: Scratch vs. Intradermal

Percutaneous (scratch/prick) testing uses CPT 95004, and intradermal testing uses 95024 (single) or 95027 (sequential). These are unit-based codes — you bill per test administered. The key documentation requirement: record each allergen tested, the technique used, and the reaction result. Without this, payers will deny or downcode.

One thing that trips practices up: billing both scratch and intradermal for the same allergen on the same day. Some payers consider this a duplicate. Know your payer policies before you bill both methods together.

Heads up: Allergen-specific IgE testing (95076, 95079) is lab-based and billed differently from skin testing. Don't mix these up — they represent different services with different coverage rules.

Immunotherapy Billing

This is where allergy practices make real money — and where billing errors are most expensive. The codes break down like this:

The 95165 code is billed in units — one unit per dose, up to the total doses prepared. Practices sometimes bill the wrong unit count or forget that this code is for professional services only, not the antigen itself.

Antigen Preparation: What You Can Bill

When your practice mixes the antigen, that preparation is a separately billable service. But the documentation has to reflect it — what was prepared, the concentration, the lot numbers, and who supervised the preparation. If your allergist isn't directly involved in preparation oversight, you may not be able to bill the professional component.

Audit risk: Billing 95165 for antigen preparation when the practice outsourced mixing to a compounding pharmacy is a common compliance error. If you didn't prepare it, you can't bill it as your professional service.

Rush Immunotherapy (SLIT and SCIT)

Sublingual immunotherapy (SLIT) doesn't have its own dedicated CPT — most practices use an unlisted code or bill it under evaluation and management. Subcutaneous immunotherapy (SCIT) has established codes. The distinction matters because SLIT reimbursement is inconsistent across payers, and some don't cover it at all.

Check your payer contracts before offering SLIT as a covered service. Billing for it and then eating the denial is a cash flow problem that compounds over months.

E&M on Immunotherapy Days

You can bill an E&M on the same day as immunotherapy if a separately identifiable service is provided. Use modifier -25. The E&M must be documented independently — you can't use the immunotherapy visit note as your E&M documentation. Payers watch for this.

Tip: Train your front desk to mark immunotherapy-only visits separately from visits that include a physician encounter. It makes the billing decision cleaner and reduces modifier errors.

Spirometry and Pulmonary Function Testing

Many allergy/immunology practices perform in-office spirometry (CPT 94010). When you're also doing allergy testing the same day, confirm that both services are independently documented and medically necessary. Some payers bundle these and won't pay both without a strong clinical rationale in the notes.

Key Documentation Requirements

ServiceMust Document
Allergy skin testingEach allergen, technique, reaction result, interpretation
Immunotherapy injectionAllergen administered, dose, site, observation time, any reactions
Antigen preparation (95165)Antigens mixed, concentrations, number of doses, supervising physician
E&M on injection daySeparate problem-focused note; modifier -25 on E&M claim

Allergy billing rewards detail. Practices with clean documentation consistently outperform on collections — and survive audits without scrambling for records they should have had all along.

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