Yesim Yilmaz Demirdag, M.D.
NPI 1134330921ActiveIndividual· Allergy & Immunology· Irvine, CA
Allergy & Immunology (M.D.) with Uc Regents, practicing in Irvine, California. Their prescriptions cost Medicare Part D more than their services did: $1,394,906 for 887 claims, against $36,317 paid for services in 2024. Genzyme Corporation was the largest of 3 companies reporting payments in 2025, $2,107 in all, mostly consulting fees. Lists Uci Health-Orange as a hospital affiliation.
Overview
| NPI | 1134330921 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | No |
| NPI issued | May 24, 2007 |
| Last updated in NPPES | Aug 27, 2020 |
| Certified by provider | Aug 27, 2020 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Allergy & Immunology Primary | 207K00000X | C166841 | CA |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 11, 2026 | No match | — |
| New York OMIG · Nov 11, 2026 | No match | — |
| Ohio Medicaid · Nov 11, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 11, 2026 | No match | — |
| Washington HCA · Nov 11, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Allergy/Immunology (CA); Practitioner - Pediatric Medicine (NY) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 216 |
|---|---|
| Services billed | 646 across 19 procedure codes |
| Paid by Medicare | $36,317 |
Part D prescriptions in 2024
| Prescriptions (claims) | 887 · 1,184 30-day fills |
|---|---|
| Patients | 128 |
| Total drug cost | $1,394,906 |
| Generic share | 47% of claims |
Education and affiliations
| Graduation year | 1990 |
|---|---|
| Medicare specialty | Allergy/Immunology |
| Telehealth | Offers telehealth |
Medical group
- Uc RegentsOrange, CA · 319 clinicians
Hospital affiliation
- Uci Health-OrangeOrange, CA
Industry payments (Open Payments)
- 2025$2,107 · 3 payments from 3 companies
- 2024$3,090 · 9 payments from 5 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Genzyme Corporation | $2,070 | 1 |
| Genentech USA, Inc. | $20.71 | 1 |
| Ars Pharmaceuticals Operations, Inc. | $16.36 | 1 |
What the 2025 payments were for
- Consulting Fee$2,070 · 1 payment
- Food and Beverage$37.07 · 2 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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