Kathryn Sewell, M.D.
Kathryn Sewell, M.D. is a Geriatric Medicine (Internal Medicine) Physician in San Francisco, CA, registered under NPI 1689652612. This provider registers 2 separate taxonomy codes, which usually means they practise across more than one recognised specialty. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
The practice address on file is 1515 BAKER ST, San Francisco, CA 94115. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| 60367 | MA | Geriatric Medicine (Internal Medicine)… primary |
| G85724 | CA | Geriatric Medicine (Internal Medicine)… |
| 60367 | MA | Rheumatology Physician |
| G85724 | CA | Rheumatology Physician |
Licences are recorded in 2 states: MA, CA. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
This NPI does not appear in the PECOS Medicare enrolment file. Providers who do not bill Medicare — or who bill only through a group's enrolment — will not appear here. It is not a sign of any problem with the registration.
Licensed in 2 states
This provider holds licences in 2 states: California and Massachusetts. The practice address on file is in San Francisco, CA, but a licence in another state usually means they see patients there too — either at a second location or by telehealth. If the address above is far from you, it is worth calling to ask whether they practise closer to where you live.
- Licence
- G85724
- Specialty
- Geriatric Medicine (Internal Medicine)…
- Licence
- 60367
- Specialty
- Geriatric Medicine (Internal Medicine)…
Licence numbers are self-reported to NPPES at registration. They do not confirm a licence is currently active, in good standing, or valid for the specialty shown — only the state board can tell you that, which is why we link to each one.
What Geriatric Medicine covers
An internist who has special knowledge of the aging process and special skills in the diagnostic, therapeutic, preventive and rehabilitative aspects of illness in the elderly. This specialist cares for geriatric patients in the patient's home, the office, long-term care settings such as nursing homes and the hospital. NUCC Health Care Provider Taxonomy, code 207RG0300X
All registered taxonomy codes
This provider registers 4 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207RG0300X | Geriatric Medicine (Internal Medicine) Physician Geriatric Medicine | 60367 | MA | primary |
| 207RG0300X | Geriatric Medicine (Internal Medicine) Physician Geriatric Medicine | G85724 | CA | |
| 207RR0500X | Rheumatology Physician Rheumatology | 60367 | MA | |
| 207RR0500X | Rheumatology Physician Rheumatology | G85724 | CA |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1689652612 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jan 9, 2006 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | M.D. |
| Practice address |
1515 BAKER ST San Francisco, CA 94115 (415) 345-1973 |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 6 | 8 | 9 | 6 | 5 | 2 | 6 | 1 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 7 | 9 | 3 | 5 | 4 | 6 | 2 |
Sum = 68 · next multiple of 10 = 70 · check digit = 2 · actual last digit = 2
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.