William Loo
NPI 1427887660 · Physician Assistant · Pomona, CA
Enrolled with Medicare as Practitioner - Physician Assistant · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Loo is a Physician Assistant provider in Pomona, CA (NPI 1427887660).
Provider details
- NPI number
- 1427887660
- Entity type
- Individual
- Primary specialty
- Physician AssistantPhysician Assistants & Advanced Practice Nursing Providers
- Sex
- Male
- Sole proprietor
- No
- License
- 65690 (CA)
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 tenure38% of score
1 yr in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
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.
Practice location
Mailing address
Registry dates
- Enumerated
- 2024-07-27
- Last updated
- 2025-01-16
- Certified
- 2025-01-16
Frequently asked questions
- What is William Loo's NPI number?
- William Loo's National Provider Identifier (NPI) is 1427887660, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Loo's specialty?
- William Loo is listed in the NPPES registry with a primary specialty of Physician Assistant (Physician Assistants & Advanced Practice Nursing Providers).
- Where is William Loo located?
- William Loo's practice location on file with NPPES is 450 E 2nd St, Pomona, CA 91766-1950.
- What is William Loo's phone number?
- The practice phone number listed in the NPPES registry for William Loo is (909) 469-5335.
- Does William Loo accept Medicare?
- William Loo is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Loo's NPI active?
- Yes — William Loo's NPI (1427887660) is active in the NPPES registry as of the last update on 2025-01-16.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.