William Tsai D O Inc
NPI 1598876856 · Family Medicine Physician · Upland, CA
Enrolled with Medicare as Part B Supplier - Clinic/Group Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Tsai D O Inc is a Family Medicine Physician organization in Upland, CA (NPI 1598876856).
Provider details
- NPI number
- 1598876856
- Entity type
- Organization
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Organization subpart
- No
- Authorized official
- William Tsai, Physician Owner(909) 985-8838
- License
- 20A7115 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
19 yrs 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
- 2006-08-31
- Last updated
- 2024-04-24
- Certified
- 2024-04-24
Frequently asked questions
- What is William Tsai D O Inc's NPI number?
- William Tsai D O Inc's National Provider Identifier (NPI) is 1598876856, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What type of organization is William Tsai D O Inc?
- William Tsai D O Inc is classified in the NPPES registry as Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is William Tsai D O Inc located?
- William Tsai D O Inc's practice location on file with NPPES is 510 N 13th Ave Ste 101, Upland, CA 91786-4973.
- What is William Tsai D O Inc's phone number?
- The practice phone number listed in the NPPES registry for William Tsai D O Inc is (909) 985-8838.
- Does William Tsai D O Inc accept Medicare?
- William Tsai D O Inc is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Who is the authorized official for William Tsai D O Inc?
- The authorized official listed on William Tsai D O Inc's NPPES record is William Tsai, Physician Owner. The authorized official registers and maintains the organization's NPI and is not necessarily its owner.
- Is William Tsai D O Inc's NPI active?
- Yes — William Tsai D O Inc's NPI (1598876856) is active in the NPPES registry as of the last update on 2024-04-24.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.