William Sierra, PA
NPI 1992721229 · Physician Assistant · West Islip, NY
William Sierra, PA is a Physician Assistant provider in West Islip, NY (NPI 1992721229).
Provider details
- NPI number
- 1992721229
- Entity type
- Individual
- Primary specialty
- Physician AssistantPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- PA
- Sex
- Male
- Sole proprietor
- No
- License
- 002312 (NY)
Specialties & taxonomies
Physician Assistants & Advanced Practice Nursing Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure33% of score
19 yrs in NPPES registry
- Profile completeness33% of score
100% of core fields populated
- Practice footprint20% of score
1 documented practice location
- Open Payments transparency13% of score
Has Open Payments disclosures (2024)
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.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$492 across 15 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
- 2006-07-13
- Last updated
- 2008-05-29
Frequently asked questions
- What is William Sierra's NPI number?
- William Sierra's National Provider Identifier (NPI) is 1992721229, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Sierra's specialty?
- William Sierra is listed in the NPPES registry with a primary specialty of Physician Assistant (Physician Assistants & Advanced Practice Nursing Providers).
- Where is William Sierra located?
- William Sierra's practice location on file with NPPES is 1000 Montauk Hwy, West Islip, NY 11795-4927.
- What is William Sierra's phone number?
- The practice phone number listed in the NPPES registry for William Sierra is (631) 376-3000.
- Is William Sierra's NPI active?
- Yes — William Sierra's NPI (1992721229) is active in the NPPES registry as of the last update on 2008-05-29.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.