Tammy Nguyen, OD
NPI 1396864575 · Optometrist · San Mateo, CA
Enrolled with Medicare as Practitioner - Optometry · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Tammy Nguyen, OD is a Optometrist provider in San Mateo, CA (NPI 1396864575).
Provider details
- NPI number
- 1396864575
- Entity type
- Individual
- Primary specialty
- OptometristEye and Vision Services Providers
- Credential
- OD
- Sex
- Female
- Sole proprietor
- No
- License
- OPT 11827 TPA (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 tenure25% of score
19 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
14 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) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 14 | $111 |
Typical Medicare-allowed amounts for these services range $111–$111 (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 · 10 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Latanoprost | 82 | 30 |
| Timolol Maleate | 77 | 20 |
| Bimatoprostbrand: Lumigan | 50 | 18 |
| Cyclosporinebrand: Restasis | 37 | 14 |
| Brimonidine Tartrate | 29 | 12 |
| Dorzolamide Hcl/Timolol Maleatbrand: Dorzolamide-Timolol | 28 | — |
| Latanoprostene Bunodbrand: Vyzulta | 17 | — |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$610 across 22 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
- 2007-03-28
- Last updated
- 2007-07-08
Frequently asked questions
- What is Tammy Nguyen's NPI number?
- Tammy Nguyen's National Provider Identifier (NPI) is 1396864575, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Tammy Nguyen's specialty?
- Tammy Nguyen is listed in the NPPES registry with a primary specialty of Optometrist (Eye and Vision Services Providers).
- Where is Tammy Nguyen located?
- Tammy Nguyen's practice location on file with NPPES is 50 S San Mateo Dr, San Mateo, CA 94401-3857.
- What is Tammy Nguyen's phone number?
- The practice phone number listed in the NPPES registry for Tammy Nguyen is (650) 342-4595.
- Does Tammy Nguyen accept Medicare?
- Tammy Nguyen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Tammy Nguyen's NPI active?
- Yes — Tammy Nguyen's NPI (1396864575) is active in the NPPES registry as of the last update on 2007-07-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.