Ernest Q. Williams, MD
NPI 1588623292ActiveIndividual· Internal Medicine, Gastroenterology· Oxford, MS
Internal Medicine, Gastroenterology (MD) with Billings Clinic Specialty Supplies and Services, LLC and 1 other group, practicing in Oxford, Mississippi. Their prescriptions cost Medicare Part D more than their services did: $1,004,611 for 3,142 claims, against $179,768 paid for services in 2024. Phathom Pharmaceuticals, Inc. was the largest of 21 companies reporting payments in 2025, $16,279 in all, mostly speaking and faculty fees. Lists Baptist Memorial Hospital North Ms and 2 other hospitals as hospital affiliations.
Overview
| NPI | 1588623292 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Mar 21, 2006 |
| Last updated in NPPES | Feb 16, 2026 |
| Certified by provider | Feb 16, 2026 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Gastroenterology Primary | 207RG0100X | 17218 | MS |
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 - Gastroenterology (MS); Practitioner - Gastroenterology (MT) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 673 |
|---|---|
| Services billed | 4,134 across 56 procedure codes |
| Paid by Medicare | $179,768 |
Part D prescriptions in 2024
| Prescriptions (claims) | 3,142 · 5,023 30-day fills |
|---|---|
| Patients | 859 |
| Total drug cost | $1,004,611 |
| Generic share | 86% of claims |
Education and affiliations
| Graduation year | 1994 |
|---|---|
| Medicare specialty | Gastroenterology |
Medical groups
- Billings Clinic Specialty Supplies and Services, LLCBillings, MT · 824 clinicians
- Gastroenterology Center of the Midsouth PLLCJackson, TN · 149 clinicians
Hospital affiliations
- Baptist Memorial Hospital North MsOxford, MS
- Baptist Memorial Hospital Union CountyNew Albany, MS
- Billings Clinic HospitalBillings, MT
Industry payments (Open Payments)
- 2025$16,279 · 80 payments from 21 companies
- 2024$16,442 · 94 payments from 22 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Phathom Pharmaceuticals, Inc. | $14,601 | 12 |
| Boston Scientific Corporation | $222.91 | 2 |
| Lilly USA, LLC | $208.17 | 6 |
| Abbvie Inc. | $147.15 | 13 |
| Genzyme Corporation | $140.16 | 6 |
What the 2025 payments were for
- Compensation for services other than consulting, including serving as faculty or as a speaker at a venue other than a continuing education program$14,190 · 7 payments
- Food and Beverage$2,089 · 73 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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