We now have four years of allergy/immunology Medicare E&M coding data following the E&M rule change in 2021, with E&M codes based on time or medical decision-making. The trend is clear: allergists’ coding patterns have continued to shift in favor of higher E&M codes over the past four years.
Medicare publicly reports specialty-specific E&M utilization data each year, which they use to identify providers who are overcoding. But this data can also tell us how allergy/immunology E&M coding patterns change over time, as well as help you see how your coding distribution for E&M services compares to other allergists.
Knowing how your E&M coding distribution stacks up against your peers is becoming increasingly important, as many carriers are implementing automatic downcoding and/or pre-payment reviews based on coding patterns. Allergists that code outside of the averages are more likely to be targeted based on payers’ AI review of claims. That doesn’t mean you should code lower than a visit deserves, but it is important to be aware of how this data is being used. Allergists should make sure their documentation justifies the coding level and appeal any denials or downcoding with this data.
2021-2025 Medicare E&M code usage for allergy/immunology is summarized below. Coding patterns have shifted significantly since the rule change in 2021. There has been a clear increase in level 4 coding and a corresponding decrease in level 3 coding for both new and existing patients over the past three years – but the shift for existing patients has been most substantial. For new patient visits, level 4 visits increased 5.9 percentage points to over 63% in 2025. Level 3 visits decreased 5.4 percentage points to 27%. The most common code used by allergists in all four years was a level 4, with level 3 being the next most common.
Allergy/Immunology Medicare E&M Distribution
New Patients
2021-2025
| New patient E&M code | 2025 Utiliz. % |
2024 Utiliz. % |
2023 Utiliz. % |
2022 Utiliz. % |
2021 Utiliz. % |
|---|---|---|---|---|---|
| 99202 | 0.6% | 1.0% | 1.4% | 1.4% | 2.0% |
| 99203 | 27.0% | 28.7% | 29.8% | 31.2% | 32.4% |
| 99204 | 63.4% | 61.0% | 59.9% | 59.1% | 57.5% |
| 99205 | 9.0% | 9.3% | 8.9% | 8.3% | 8.1% |
| Total | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% |
|
Source: Evaluation and Management (E&M) Codes by Specialty Reports | CMS (2021-2024) and CMS Physician/Supplier Procedure Summary (2025) Coding shifts for existing patient visits were even more marked. Level 4 usage increased by 9.7 percentage points to over 52% in 2025 and is clearly the most common E&M code used by allergists. Level 3 coding dropped 8.5 percentage points to 37.2% in 2025. Levels 1, 2 and 5 continue to be used infrequently – but we are seeing a small increase in coding for level 5 and slight decreases in coding for levels 1 and 2. |
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Allergy/Immunology Medicare E&M Distribution
Existing Patients
2021-2025
| Existing patient E&M code | 2025 Utiliz. % | 2024 Utiliz. % | 2023 Utiliz. % | 2022 Utiliz. % | 2021 Utiliz. % |
|---|---|---|---|---|---|
| 99211 | 2.6% | 2.5% | 2.6% | 3.0% | 3.4% |
| 99212 | 2.7% | 3.2% | 3.7% | 4.1% | 4.6% |
| 99213 | 37.2% | 39.8% | 41.9% | 44.0% | 45.7% |
| 99214 | 52.5% | 49.8% | 47.7% | 45.0% | 42.8% |
| 99215 | 4.9% | 4.6% | 4.1% | 3.9% | 3.5% |
| Total | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% |
| Source: Evaluation and Management (E&M) Codes by Specialty Reports | CMS (2021-2024) and CMS Physician/Supplier Procedure Summary (2025) | |||||
We encourage you to pull your own historical coding data from your practice management system to see how it compares to the average Medicare coding distribution for allergists/immunologists. Keep in mind, however, that every practice has a different demographic of patients, and your own experience, especially with non-Medicare patients, may not be directly comparable to the Medicare average.
If you or your billing staff needs a refresher on E&M coding based on time or medical decision making, we encourage you to check out the College’s Coding Toolkit. We have easy-to-understand articles on the E&M coding rules, plus expert advice on many common (and not-so-common) allergy coding questions. Our Coding FAQ database should be the first place you look when you have an allergy coding question!
Special thanks to Robert Ellis, CPA, the CFO of the Carolina Asthma & Allergy Center, for sharing the 2025 data cited in this article.
