CLARK S. TSAI, M.D., INC.
CLARK S. TSAI, M.D., INC. is an organization registered with the National Plan and Provider Enumeration System (NPPES) under NPI 1487930996, based in Oakland, CA. It is classified under Ophthalmology Physician.
Getting there
The practice address on file is 350 30TH ST SUITE 444, Oakland, CA 94609. 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 |
|---|---|---|
| G76192 | CA | Ophthalmology Physician primary |
This provider holds licence G76192 issued in CA. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
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.
What Ophthalmology covers
An ophthalmologist has the knowledge and professional skills needed to provide comprehensive eye and vision care. Ophthalmologists are medically trained to diagnose, monitor and medically or surgically treat all ocular and visual disorders. This includes problems affecting the eye and its component structures, the eyelids, the orbit and the visual pathways. In so doing, an ophthalmologist prescribes vision services, including glasses and contact lenses. NUCC Health Care Provider Taxonomy, code 207W00000X
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-2 identifies an organization — a clinic, hospital, group practice, laboratory, or supplier. Individual clinicians working there hold their own NPI-1 numbers separately, so a bill may reference both.
| NPI | 1487930996 valid check digit |
|---|---|
| Entity type | Organization (NPI-2) |
| Enumeration date | Oct 28, 2011 |
| Last updated | Dec 14, 2011 |
| Status | Active |
| Practice address |
350 30TH ST SUITE 444 Oakland, CA 94609 (925) 864-8886 Fax (925) 689-7748 |
| Mailing address |
2700 GRANT ST SUITE 100 Concord, CA 94520 |
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 | 4 | 8 | 7 | 9 | 3 | 0 | 9 | 9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 4 | 7 | 7 | 9 | 3 | 0 | 9 | 9 |
Sum = 74 · next multiple of 10 = 80 · check digit = 6 · actual last digit = 6
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.