William Oh, M.D.
NPI 1225095581 · Medical Oncology Physician · Greenwich, CT
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Oh, M.D. is a Medical Oncology Physician provider in Greenwich, CT (NPI 1225095581).
Provider details
- NPI number
- 1225095581
- Entity type
- Individual
- Primary specialty
- Medical Oncology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- 255056 (NY)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
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
3 documented practice locations
- Medicare service volume (vs. specialty peers)25% of score
480 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 | 335 | $104 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 58 | $105 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 35 | $70 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 21 | $72 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 16 | $135 |
| Telephone Medical Discussion With Physician, 11-20 Minutes |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 3 distinct drugs on file.
| Drug | Part D claims (2024) |
|---|---|
| Darolutamidebrand: Nubeqa | 26 |
| Tamsulosin Hcl | 12 |
| Venlafaxine Hclbrand: Venlafaxine Hcl Er | 12 |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means no Part D record, never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$27,496 across 13 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
Additional practice locations (2)
- 5 Perryridge RdGreenwich, CT 06830-4697Phone: (203) 863-3000
- 35 W Park AveNew Haven, CT 06511-4043Phone: (203) 688-4242
Registry dates
- Enumerated
- 2006-04-28
- Last updated
- 2024-12-11
- Certified
- 2024-12-11
Frequently asked questions
- What is William Oh's NPI number?
- William Oh's National Provider Identifier (NPI) is 1225095581, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Oh's specialty?
- William Oh is listed in the NPPES registry with a primary specialty of Medical Oncology Physician (Allopathic & Osteopathic Physicians).
- Where is William Oh located?
- William Oh's practice location on file with NPPES is 77 Lafayette Pl, Greenwich, CT 06830-5437.
- What is William Oh's phone number?
- The practice phone number listed in the NPPES registry for William Oh is (203) 863-3700.
- Does William Oh accept Medicare?
- William Oh is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Oh's NPI active?
- Yes — William Oh's NPI (1225095581) is active in the NPPES registry as of the last update on 2024-12-11.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.