Mary Sienkiewicz, ARNP
NPI 1245413533 · Nurse Practitioner · Bellevue, WA
Enrolled with Medicare as Practitioner - Nurse Practitioner · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mary Sienkiewicz, ARNP is a Nurse Practitioner provider in Bellevue, WA (NPI 1245413533).
Provider details
- NPI number
- 1245413533
- Entity type
- Individual
- Primary specialty
- Nurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- ARNP
- Sex
- Female
- Sole proprietor
- No
- License
- RN00166727 (WA)
Specialties & taxonomies
Physician Assistants & Advanced Practice Nursing Providers
Nursing Service Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
18 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
- 2007-12-10
- Last updated
- 2018-11-29
Frequently asked questions
- What is Mary Sienkiewicz's NPI number?
- Mary Sienkiewicz's National Provider Identifier (NPI) is 1245413533, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mary Sienkiewicz's specialty?
- Mary Sienkiewicz is listed in the NPPES registry with a primary specialty of Nurse Practitioner (Physician Assistants & Advanced Practice Nursing Providers).
- Where is Mary Sienkiewicz located?
- Mary Sienkiewicz's practice location on file with NPPES is 1231 116th Ave Ne Ste 950, Bellevue, WA 98004-3832.
- What is Mary Sienkiewicz's phone number?
- The practice phone number listed in the NPPES registry for Mary Sienkiewicz is (206) 328-7734.
- Does Mary Sienkiewicz accept Medicare?
- Mary Sienkiewicz is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mary Sienkiewicz's NPI active?
- Yes — Mary Sienkiewicz's NPI (1245413533) is active in the NPPES registry as of the last update on 2018-11-29.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.