William Henderson
William Henderson is an Allergy & Immunology (Internal Medicine) Physician in Seattle, WA, registered under NPI 1639254436. 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 UNIVERSITY OF WASHINGTON MEDICAL CTR 1959 NE PACIFIC ST, Seattle, WA 98195. 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 |
|---|---|---|
| MD00017040 | WA | Allergy & Immunology (Internal Medicine)… primary |
| MD00017040 | WA | Internal Medicine Physician |
This provider holds licence MD00017040 issued in WA. 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 Allergy & Immunology covers
An internist doctor of osteopathy that specializes in the treatment of allergy and immunologic disorders. A doctor of osteopathy that is board eligible/certified by the American Osteopathic Board of Internal Medicine can obtain a Certificate of Special Qualifications in the field of Allergy & Immunology. NUCC Health Care Provider Taxonomy, code 207RA0201X
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 | |
|---|---|---|---|---|
| 207RA0201X | Allergy & Immunology (Internal Medicine) Physician Allergy & Immunology | MD00017040 | WA | primary |
| 207R00000X | Internal Medicine Physician | MD00017040 | WA |
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 | 1639254436 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Oct 27, 2006 |
| Last updated | Dec 3, 2013 |
| Status | Active |
| Sole proprietor | No |
| Gender | Male |
| Practice address |
UNIVERSITY OF WASHINGTON MEDICAL CTR 1959 NE PACIFIC ST Seattle, WA 98195 (206) 598-4615 |
| Mailing address |
PO BOX 50095 Seattle, WA 98145 |
| Other identifiers |
0231176
· Other (WA) 1639254436 · Medicaid (WA) 1850 · Other |
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 | 3 | 9 | 2 | 5 | 4 | 4 | 3 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 6 | 9 | 4 | 5 | 8 | 4 | 6 |
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.