Sara Holmes, MD
Sara Holmes, MD is a Nephrology Physician in Novato, CA, registered under NPI 1801174479.
Getting there
The practice address on file is 97 SAN MARIN DR, Novato, CA 94945. 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 |
|---|---|---|
| MD600004898 | DC | Nephrology Physician primary |
| MD443610 | PA | Nephrology Physician |
| A133361 | CA | Nephrology Physician |
Licences are recorded in 3 states: DC, PA, CA. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
- Status
- Approved
- Provider type
- Practitioner - Nephrology
- PAC ID
- 8426229972
- Enrollment ID
- I20150526001126
Medicare enrolment is recorded as approved under the provider type Practitioner - Nephrology. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
Licensed in 3 states
This provider holds licences in 3 states: California, District of Columbia and Pennsylvania. The practice address on file is in Novato, 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
- A133361
- Specialty
- Nephrology Physician
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 Nephrology covers
An internist who treats disorders of the kidney, high blood pressure, fluid and mineral balance and dialysis of body wastes when the kidneys do not function. This specialist consults with surgeons about kidney transplantation. NUCC Health Care Provider Taxonomy, code 207RN0300X
All registered taxonomy codes
This provider registers 3 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207RN0300X | Nephrology Physician Nephrology | MD600004898 | DC | primary |
| 207RN0300X | Nephrology Physician Nephrology | MD443610 | PA | |
| 207RN0300X | Nephrology Physician Nephrology | A133361 | 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 | 1801174479 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jul 29, 2011 |
| Last updated | Nov 5, 2025 |
| Status | Active |
| Sole proprietor | No |
| Credential | MD |
| Practice address |
97 SAN MARIN DR Novato, CA 94945 (415) 899-7880 Fax (415) 899-7815 |
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 | 8 | 0 | 1 | 1 | 7 | 4 | 4 | 7 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 8 | 0 | 1 | 2 | 7 | 8 | 4 | 5 |
Sum = 61 · next multiple of 10 = 70 · check digit = 9 · actual last digit = 9
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.