William Henderson
NPI 1639254436 · Allergy & Immunology (Internal Medicine) Physician · Seattle, WA
William Henderson is a Allergy & Immunology (Internal Medicine) Physician provider in Seattle, WA (NPI 1639254436).
Provider details
- NPI number
- 1639254436
- Entity type
- Individual
- Primary specialty
- Allergy & Immunology (Internal Medicine) PhysicianAllopathic & Osteopathic Physicians
- Sex
- Male
- Sole proprietor
- No
- License
- MD00017040 (WA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
19 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-10-27
- Last updated
- 2013-12-03
Frequently asked questions
- What is William Henderson's NPI number?
- William Henderson's National Provider Identifier (NPI) is 1639254436, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Henderson's specialty?
- William Henderson is listed in the NPPES registry with a primary specialty of Allergy & Immunology (Internal Medicine) Physician (Allopathic & Osteopathic Physicians).
- Where is William Henderson located?
- William Henderson's practice location on file with NPPES is University of Washington Medical Ctr, Seattle, WA 98195-6166.
- What is William Henderson's phone number?
- The practice phone number listed in the NPPES registry for William Henderson is (206) 598-4615.
- Is William Henderson's NPI active?
- Yes — William Henderson's NPI (1639254436) is active in the NPPES registry as of the last update on 2013-12-03.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.