JOHN T ARMSTRONG JR MD INC
JOHN T ARMSTRONG JR MD INC is an organization registered with the National Plan and Provider Enumeration System (NPPES) under NPI 1598830564, based in Napa, CA. It is classified under Gynecology Physician.
Getting there
The practice address on file is 3434 VILLA LN STE 360, Napa, CA 94558. 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 |
|---|---|---|
| C37899 | CA | Gynecology Physician primary |
This provider holds licence C37899 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
- Part B Supplier - Clinic/group Practice
- PAC ID
- 8224110564
- Enrollment ID
- O20080125000406
Medicare enrolment is recorded as approved under the provider type Part B Supplier - Clinic/group Practice. 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 Gynecology covers
A physician who specializes in diagnosis, treatment, and management of patients with gynecologic conditions. NUCC Health Care Provider Taxonomy, code 207VG0400X
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 | 1598830564 valid check digit |
|---|---|
| Entity type | Organization (NPI-2) |
| Enumeration date | Nov 22, 2006 |
| Last updated | Aug 28, 2014 |
| Status | Active |
| Practice address |
3434 VILLA LN STE 360 Napa, CA 94558 (707) 257-4317 |
| Mailing address |
3010 BEARD RD Napa, CA 94558 |
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 | 5 | 9 | 8 | 8 | 3 | 0 | 5 | 6 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 5 | 9 | 8 | 7 | 3 | 0 | 5 | 3 |
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.