Quick answers
- Which hospitals does Mark W. Layton work at?
- Medicare's official clinician data lists Mark W. Layton at 3 hospitals: Mason General Hospital & Family of Clinics, Summit Pacific Medical Center and Willapa Harbor Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Mark W. Layton see patients?
- Medicare's clinician data lists 1 practice location in Olympia, WA. Call before your visit to confirm the address.
- What is Mark W. Layton's specialty?
- Medicare lists Rheumatology as the primary specialty, and also Internal Medicine.
- Does Mark W. Layton accept Medicare assignment?
- Yes. Medicare's clinician data says Mark W. Layton accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
- What is the phone number for Mark W. Layton?
- (360) 754-6700, as listed in official Medicare / NPI Registry data.
- What is Mark W. Layton's NPI number?
- 1891846077. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Mark W. Layton works
Medicare's Facility Affiliation Data lists Mark W. Layton at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Mason General Hospital & Family of ClinicsShelton, WA · Critical Access Hospital · CCN 501336
- Summit Pacific Medical CenterElma, WA · Critical Access Hospital · CCN 501304
- Willapa Harbor HospitalSouth Bend, WA · Critical Access Hospital · CCN 501303
Practice locations
Addresses where Mark W. Layton is enrolled with Medicare (CMS data updated 2026-10-02).
- 1212 Harrison Ave NWOlympia, WA 98502 (360) 754‑6700
Specialties
- Rheumatologyprimary
- Internal Medicinealso
Other rheumatologists in Washington
Clinicians with the same Medicare primary specialty in Washington — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Washington School Of Medicine |
| Graduation year | 1982 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1891846077 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians