John Williams, D.O.
NPI 1144220369 · Internal Medicine Physician · Willits, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
John Williams, D.O. is a Internal Medicine Physician provider in Willits, CA (NPI 1144220369).
Provider details
- NPI number
- 1144220369
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- D.O.
- Sex
- Male
- Sole proprietor
- Yes
- License
- 20A6027 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
20 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
1,874 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
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 .
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 | 832 | $124 |
| Testing for Presence of Drug, Read By Direct Observation80305 | 334 | $12 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 235 | $174 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 176 | $88 |
| Hemoglobin A1c Level83036 | 58 | $10 |
| Subsequent Nursing Facility Care With High Level of Medical Decision Making, Per Day, If Using Time, at Least 45 Minutes99310 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 177 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 442 | 99 |
| Amlodipine Besylate | 429 | 87 |
| Gabapentin | 399 | 66 |
| Hydrocodone/Acetaminophenbrand: Hydrocodone-Acetaminophen | 377 | 67 |
| Levothyroxine Sodium | 305 | 58 |
| Oxycodone Hcl | 277 | 35 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$546 across 26 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2005-07-29
- Last updated
- 2018-12-19
Frequently asked questions
- What is John Williams's NPI number?
- John Williams's National Provider Identifier (NPI) is 1144220369, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is John Williams's specialty?
- John Williams is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is John Williams located?
- John Williams's practice location on file with NPPES is 1712 S Main St, Willits, CA 95490-4400.
- What is John Williams's phone number?
- The practice phone number listed in the NPPES registry for John Williams is (707) 459-5585.
- Does John Williams accept Medicare?
- John Williams is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is John Williams's NPI active?
- Yes — John Williams's NPI (1144220369) is active in the NPPES registry as of the last update on 2018-12-19.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.