Chelsea Thomsen, M.D., M.S.P.H
NPI 1003227927 · Internal Medicine Physician · San Francisco, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Chelsea Thomsen, M.D., M.S.P.H is a Internal Medicine Physician provider in San Francisco, CA (NPI 1003227927).
Provider details
- NPI number
- 1003227927
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D., M.S.P.H
- Sex
- Female
- Sole proprietor
- No
- License
- 50576 (AZ)
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 tenure28% of score
12 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
2 documented practice locations
- Medicare service volume (vs. specialty peers)28% of score
191 Medicare services, 2024 (ranked within specialty)
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 methodology.
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 | 62 | $109 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 51 | $153 |
| Insertion of Needle Into Vein for Collection of Blood Sample36415 | 48 | $9 |
| Visit Complexity Inherent to Evaluation and Management Associated With Medical Care Services That Serve As the Continuing Focal Point for All Needed Health Care Services And/Or With Medical Care Services That Are Part of Ongoing Care Related to a Patient'SG2211 | 18 | $19 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 12 | $156 |
Typical Medicare-allowed amounts for these services range $9–$156 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, 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 · 3 distinct drugs on file.
| Drug | Part D claims (2024) |
|---|---|
| Atorvastatin Calcium | 22 |
| Levothyroxine Sodium | 16 |
| Losartan Potassium | 12 |
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.
Practice location
Mailing address
Additional practice locations (1)
- 1998 Market StSan Francisco, CA 94102-6228Phone: (415) 790-6040
Registry dates
- Enumerated
- 2014-05-13
- Last updated
- 2025-03-14
- Certified
- 2025-03-14
Frequently asked questions
- What is Chelsea Thomsen's NPI number?
- Chelsea Thomsen's National Provider Identifier (NPI) is 1003227927, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Chelsea Thomsen's specialty?
- Chelsea Thomsen is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Chelsea Thomsen located?
- Chelsea Thomsen's practice location on file with NPPES is 2 W Portal Ave, San Francisco, CA 94127-1304.
- What is Chelsea Thomsen's phone number?
- The practice phone number listed in the NPPES registry for Chelsea Thomsen is (415) 291-0480.
- Does Chelsea Thomsen accept Medicare?
- Chelsea Thomsen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Chelsea Thomsen's NPI active?
- Yes — Chelsea Thomsen's NPI (1003227927) is active in the NPPES registry as of the last update on 2025-03-14.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.