William Tan, D.O.
NPI 1891112306 · Family Medicine Physician · Olympia Fields, IL
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Tan, D.O. is a Family Medicine Physician provider in Olympia Fields, IL (NPI 1891112306).
Provider details
- NPI number
- 1891112306
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- D.O.
- Sex
- Male
- Sole proprietor
- No
- License
- 036144064 (IL)
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
12 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
1,217 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 | 373 | $132 |
| Hemoglobin A1c Level83036 | 239 | $9 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 193 | $134 |
| Administration of Influenza Virus VaccineG0008 | 130 | $34 |
| Injection of Drug Or Substance Under Skin Or Into Muscle96372 | 65 | $15 |
| Visit Complexity Inherent to Evaluation and Management Associated With Medical Care Services That Serve As the Continuing Focal Point for All Needed Health Care Services And/Or With Medical Care Services That Are Part of Ongoing Care Related to a Patient'SG2211 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 132 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 479 | 208 |
| Amlodipine Besylate | 293 | 132 |
| Losartan Potassium | 248 | 104 |
| Hydrocodone/Acetaminophenbrand: Hydrocodone-Acetaminophen | 232 | 39 |
| Metoprolol Succinate | 194 | 85 |
| Hydrochlorothiazide | 192 | 78 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$23 across 1 record (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
- 2014-03-21
- Last updated
- 2021-12-25
- Certified
- 2021-12-25
Frequently asked questions
- What is William Tan's NPI number?
- William Tan's National Provider Identifier (NPI) is 1891112306, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Tan's specialty?
- William Tan is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is William Tan located?
- William Tan's practice location on file with NPPES is 20060 Governors Dr Ste 204, Olympia Fields, IL 60461-1099.
- What is William Tan's phone number?
- The practice phone number listed in the NPPES registry for William Tan is (708) 283-8300.
- Does William Tan accept Medicare?
- William Tan is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Tan's NPI active?
- Yes — William Tan's NPI (1891112306) is active in the NPPES registry as of the last update on 2021-12-25.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.