Yishui Chen, MD
Yishui Chen, MD is a Sleep Medicine (Internal Medicine) Physician in Novato, CA, registered under NPI 1619546884. This provider registers 2 separate taxonomy codes, which usually means they practise across more than one recognised specialty.
Getting there
The practice address on file is 100 ROWLAND WAY STE 300, 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 |
|---|---|---|
| A201576 | CA | Sleep Medicine (Internal Medicine)… primary |
| A201576 | CA | Neurology Physician |
This provider holds licence A201576 issued in CA. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
- Status
- Approved
- Provider type
- Order And Referring Only - Neurology
- PAC ID
- 4880096320
Enrolled in Medicare 2 times, across 2 states:
| State | Enrollment ID | Provider type |
|---|---|---|
| Iowa | I20210707001419 | Order And Referring Only - Neurology |
| California | I20250529001877 | Order And Referring Only - Sleep Medicine |
Medicare enrolment is recorded as approved under the provider type Order And Referring Only - Neurology. There are 2 separate enrolment records across 2 states (IA, CA). Multiple enrolments usually mean the provider bills Medicare from more than one practice location, or has kept an earlier enrolment after moving. Each record carries its own enrolment ID, listed above. 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.
What Sleep Medicine covers
An Internist who practices Sleep Medicine is certified in the subspecialty of sleep medicine and specializes in the clinical assessment, physiologic testing, diagnosis, management and prevention of sleep and circadian rhythm disorders. Sleep specialists treat patients of any age and use multidisciplinary approaches. Disorders managed by sleep specialists include, but are not limited to, sleep related breathing disorders, insomnia, hypersomnias, circadian rhythm sleep disorders, parasomnias and sleep related movement disorders. NUCC Health Care Provider Taxonomy, code 207RS0012X
All registered taxonomy codes
This provider registers 2 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207RS0012X | Sleep Medicine (Internal Medicine) Physician Sleep Medicine | A201576 | CA | primary |
| 2084N0400X | Neurology Physician Neurology | A201576 | 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 | 1619546884 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jun 22, 2021 |
| Last updated | May 22, 2026 |
| Status | Active |
| Sole proprietor | No |
| Credential | MD |
| Practice address |
100 ROWLAND WAY STE 300 Novato, CA 94945 (415) 878-0225 Fax (415) 878-0215 |
| Mailing address |
550 KIRKHAM ST APT 5 San Francisco, CA 94122 |
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 | 1 | 9 | 5 | 4 | 6 | 8 | 8 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 2 | 9 | 1 | 4 | 3 | 8 | 7 |
Sum = 66 · next multiple of 10 = 70 · check digit = 4 · actual last digit = 4
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.