John Duddy, M.D.
John Duddy, M.D. is an Orthopaedic Foot and Ankle Surgery Physician in Anchorage, AK, registered under NPI 1629132022. This provider registers 3 separate taxonomy codes, which usually means they practise across more than one recognised specialty.
Getting there
The practice address on file is 2741 DEBARR RD STE C305, Anchorage, AK 99508. 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 |
|---|---|---|
| 4235 | AK | Orthopaedic Surgery Physician |
| 4235 | AK | Orthopaedic Surgery of the Spine Physician |
| 4235 | AK | Orthopaedic Foot and Ankle Surgery… primary |
This provider holds licence 4235 issued in AK. 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 Foot and Ankle Surgery covers
Recognized by several state medical boards as a fellowship subspecialty program of orthopaedic surgery, foot and ankle surgeons deal with adult reconstructive foot and ankle surgery, adult foot and ankle trauma, sports medicine foot and ankle, and children's foot and ankle reconstructive surgery. NUCC Health Care Provider Taxonomy, code 207XX0004X
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 | |
|---|---|---|---|---|
| 207X00000X | Orthopaedic Surgery Physician | 4235 | AK | |
| 207XS0117X | Orthopaedic Surgery of the Spine Physician Orthopaedic Surgery of the Spine | 4235 | AK | |
| 207XX0004X | Orthopaedic Foot and Ankle Surgery Physician Foot and Ankle Surgery | 4235 | AK | primary |
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 | 1629132022 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Dec 20, 2006 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | No |
| Gender | Male |
| Credential | M.D. |
| Practice address |
2741 DEBARR RD STE C305 Anchorage, AK 99508 (907) 278-8141 Fax (907) 279-3527 |
| Other identifiers |
MD1419
· Medicaid (AK) |
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 | 2 | 9 | 1 | 3 | 2 | 0 | 2 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 4 | 9 | 2 | 3 | 4 | 0 | 4 |
Sum = 58 · next multiple of 10 = 60 · 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.