Tonya an, MD
NPI 1699292045 · Orthopaedic Surgery Physician · Stanford, CA
Enrolled with Medicare as Practitioner - Orthopedic Surgery · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Tonya an, MD is a Orthopaedic Surgery Physician provider in Stanford, CA (NPI 1699292045).
Provider details
- NPI number
- 1699292045
- Entity type
- Individual
- Primary specialty
- Orthopaedic Surgery PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- A153483 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
8 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
3 documented practice locations
- Medicare service volume (vs. specialty peers)25% of score
748 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 Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 287 | $153 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 160 | $109 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 100 | $196 |
| Aspiration And/Or Injection of Fluid From Medium Joint20605 | 49 | $72 |
| New Patient Office Or Other Outpatient Visit With Low Level of Medical Decision Making, If Using Time, 30 Minutes Or More99203 | 48 | $134 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 4 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Ibuprofen | 52 | 30 |
| Oxycodone Hcl | 29 | 16 |
| Tramadol Hcl | 23 | 22 |
| Gabapentin | 19 | — |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means no Part D record, never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$949 across 12 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
Additional practice locations (2)
- 444 S San Vicente Blvd Ste 603Los Angeles, CA 90048-4178Phone: (310) 423-8900
- 523 E 72nd St Fl 5New York, NY 10021-4099Phone: (616) 856-0467
Registry dates
- Enumerated
- 2017-08-26
- Last updated
- 2024-04-23
- Certified
- 2024-04-23
Frequently asked questions
- What is Tonya an's NPI number?
- Tonya an's National Provider Identifier (NPI) is 1699292045, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Tonya an's specialty?
- Tonya an is listed in the NPPES registry with a primary specialty of Orthopaedic Surgery Physician (Allopathic & Osteopathic Physicians).
- Where is Tonya an located?
- Tonya an's practice location on file with NPPES is 300 Pasteur Dr, Stanford, CA 94305-2200.
- What is Tonya an's phone number?
- The practice phone number listed in the NPPES registry for Tonya an is (650) 723-4000.
- Does Tonya an accept Medicare?
- Tonya an is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Tonya an's NPI active?
- Yes — Tonya an's NPI (1699292045) is active in the NPPES registry as of the last update on 2024-04-23.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.