Margaret Hollister Sigman
NPI 1447461108ActiveIndividual· Allergy & Immunology· Midlothian, VA
Allergy & Immunology with Advanced Allergy and Asthma of Virginia, practicing in Midlothian, Virginia. Their prescriptions cost Medicare Part D more than their services did: $154,804 for 1,093 claims, against $72,271 paid for services in 2024. Astrazeneca Pharmaceuticals LP was the largest of 20 companies reporting payments in 2025, $2,894 in all, mostly food and beverage.
Overview
| NPI | 1447461108 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Sole proprietor | No |
| NPI issued | May 24, 2007 |
| Last updated in NPPES | Mar 10, 2017 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Allergy & Immunology Primary | 207K00000X | 0101253799 | VA |
| Pediatrics | 208000000X | 200801988 | NC |
| Student in an Organized Health Care Education/Training Program | 390200000X | — | — |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Oct 9, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 10, 2026 | No match | — |
| New York OMIG · Nov 10, 2026 | No match | — |
| Ohio Medicaid · Nov 10, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 10, 2026 | No match | — |
| Washington HCA · Nov 10, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Allergy/Immunology (VA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 157 |
|---|---|
| Services billed | 6,490 across 10 procedure codes |
| Paid by Medicare | $72,271 |
Part D prescriptions in 2024
| Prescriptions (claims) | 1,093 · 1,776 30-day fills |
|---|---|
| Patients | 160 |
| Total drug cost | $154,804 |
| Generic share | 78% of claims |
Education and affiliations
| Graduation year | 2003 |
|---|---|
| Medicare specialty | Allergy/Immunology |
| Telehealth | Offers telehealth |
Medical group
- Advanced Allergy and Asthma of VirginiaGlen Allen, VA · 2 clinicians
Industry payments (Open Payments)
- 2025$2,894 · 152 payments from 20 companies
- 2024$2,394 · 123 payments from 14 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Astrazeneca Pharmaceuticals LP | $756.16 | 36 |
| Glaxosmithkline, LLC. | $430.43 | 18 |
| Regeneron Healthcare Solutions, Inc. | $350.20 | 16 |
| Novartis Pharmaceuticals Corporation | $221.23 | 12 |
| Takeda Pharmaceuticals U.S.A., Inc. | $186.06 | 13 |
What the 2025 payments were for
- Food and Beverage$2,894 · 152 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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