Don Williams, MD
NPI 1447288287 · Internal Medicine Physician · Oak Park, IL
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Don Williams, MD is a Internal Medicine Physician provider in Oak Park, IL (NPI 1447288287).
Provider details
- NPI number
- 1447288287
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 036081395 (IL)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
19 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
483 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 298 | $136 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 131 | $140 |
| Administration of Influenza Virus VaccineG0008 | 38 | $34 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 16 | $97 |
Typical Medicare-allowed amounts for these services range $34–$140 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 86 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 357 | 100 |
| Pantoprazole Sodium | 174 | 51 |
| Alprazolam | 164 | 45 |
| Lisinopril | 151 | 46 |
| Metformin Hcl | 151 | 39 |
| Gabapentin | 144 | 42 |
| Amlodipine Besylate |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-06-29
- Last updated
- 2022-05-19
- Certified
- 2021-04-27
Frequently asked questions
- What is Don Williams's NPI number?
- Don Williams's National Provider Identifier (NPI) is 1447288287, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Don Williams's specialty?
- Don Williams is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Don Williams located?
- Don Williams's practice location on file with NPPES is 1100 Lake St Ste 230, Oak Park, IL 60301-1095.
- What is Don Williams's phone number?
- The practice phone number listed in the NPPES registry for Don Williams is (331) 221-9001.
- Does Don Williams accept Medicare?
- Don Williams is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Don Williams's NPI active?
- Yes — Don Williams's NPI (1447288287) is active in the NPPES registry as of the last update on 2022-05-19.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.