William O'Brien, PA
NPI 1649993841 · Physician Assistant · Livingston, NJ
Enrolled with Medicare as Practitioner - Physician Assistant · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William O'Brien, PA is a Physician Assistant provider in Livingston, NJ (NPI 1649993841).
Provider details
- NPI number
- 1649993841
- Entity type
- Individual
- Primary specialty
- Physician AssistantPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- PA
- Sex
- Male
- Sole proprietor
- No
Specialties & taxonomies
Physician Assistants & Advanced Practice Nursing Providers
- Physician Assistant363A00000X
Physician Assistants & Advanced Practice Nursing Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
3 yrs in NPPES registry
- Profile completeness25% of score
83% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
25 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) |
|---|---|---|
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 13 | $155 |
| Critical Care, First 30-74 Minutes99291 | 12 | $175 |
Typical Medicare-allowed amounts for these services range $155–$175 (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 · 2 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Naproxen | 15 | 15 |
| Cyclobenzaprine Hcl | 11 | — |
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.
$46 across 3 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
- 2022-09-22
- Last updated
- 2024-06-27
- Certified
- 2024-06-27
Frequently asked questions
- What is William O'Brien's NPI number?
- William O'Brien's National Provider Identifier (NPI) is 1649993841, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William O'Brien's specialty?
- William O'Brien is listed in the NPPES registry with a primary specialty of Physician Assistant (Physician Assistants & Advanced Practice Nursing Providers).
- Where is William O'Brien located?
- William O'Brien's practice location on file with NPPES is 94 Old Short Hills Rd, Livingston, NJ 07039-5672.
- What is William O'Brien's phone number?
- The practice phone number listed in the NPPES registry for William O'Brien is (973) 322-5000.
- Does William O'Brien accept Medicare?
- William O'Brien is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William O'Brien's NPI active?
- Yes — William O'Brien's NPI (1649993841) is active in the NPPES registry as of the last update on 2024-06-27.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.