Diana Nguyen, OD
NPI 1659955201 · Optometrist · Livermore, CA
Enrolled with Medicare as Practitioner - Optometry · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Diana Nguyen, OD is a Optometrist provider in Livermore, CA (NPI 1659955201).
Provider details
- NPI number
- 1659955201
- Entity type
- Individual
- Primary specialty
- OptometristEye and Vision Services Providers
- Credential
- OD
- Sex
- Female
- Sole proprietor
- No
- License
- 34790 (CA)
Specialties & taxonomies
Eye and Vision Services Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
5 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
- 2021-05-10
- Last updated
- 2021-05-10
- Certified
- 2021-05-10
Frequently asked questions
- What is Diana Nguyen's NPI number?
- Diana Nguyen's National Provider Identifier (NPI) is 1659955201, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Diana Nguyen's specialty?
- Diana Nguyen is listed in the NPPES registry with a primary specialty of Optometrist (Eye and Vision Services Providers).
- Where is Diana Nguyen located?
- Diana Nguyen's practice location on file with NPPES is 4423 First St, Livermore, CA 94551-4915.
- What is Diana Nguyen's phone number?
- The practice phone number listed in the NPPES registry for Diana Nguyen is (925) 292-0025.
- Does Diana Nguyen accept Medicare?
- Diana Nguyen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Diana Nguyen's NPI active?
- Yes — Diana Nguyen's NPI (1659955201) is active in the NPPES registry as of the last update on 2021-05-10.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.