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MARY DAWN SIENKIEWICZ ARNP
NPI 1245413533
Nurse Practitioner in Bellevue, WA

Active since December 10, 2007PECOS Enrolled
93.09/100
CMS Quality Rating
1231 116TH AVE NE STE 950, BELLEVUE, WA 98004(206) 328-7734 Get Directions Write a Review

NPPES record last updated: November 29, 2018. Verified against the NPPES registry weekly; last sync: October 18, 2026.

Record update history: Nov 29, 2018, Mar 16, 2018 (2 updates tracked since 2018).

About Mary Dawn Sienkiewicz Arnp NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

MARY DAWN SIENKIEWICZ ARNP (NPI 1245413533) is an individual nurse practitioner in Bellevue, Washington, licensed in Washington (AP30007980) and active in the NPI registry since December 2007. She is enrolled in Medicare PECOS.

NPPES Registry Identity

NPI1245413533
Entity TypeIndividualFemale
Primary Taxonomy363L00000X
Provider Legal NameMARY DAWN SIENKIEWICZCredential: ARNP
Location Address1231 116TH AVE NE STE 950Bellevue, WA 98004-3832
Mailing Address2612 Ne 137th StSeattle, WA 98125-3442
Phone(206) 328-7734
Sole ProprietorNo
Enumeration DateDecember 10, 2007
Last NPPES UpdateNovember 29, 20182 updates tracked since enumeration
✔ NPI 1245413533 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyNurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers
Taxonomy Code363L00000X
License✔ Licensed in WA · AP30007980
Definition
(1) A registered nurse provider with a graduate degree in nursing prepared for advanced practice involving independent and interdependent decision making and direct accountability for clinical judgment across the health care continuum or in a certified specialty. (2) A registered nurse who has completed additional training beyond basic nursing education and who provides primary health care services in accordance with state nurse practice laws or statutes. Tasks performed by nurse practitioners vary with practice requirements mandated by geographic, political, economic, and social factors. Nurse practitioner specialists include, but are not limited to, family nurse practitioners, gerontological nurse practitioners, pediatric nurse practitioners, obstetric-gynecologic nurse practitioners, and school nurse practitioners.
Also ListedRegistered NurseTaxonomy 163W00000X · License RN00166727 (WA)
1231 116TH AVE NE STE 950, Bellevue, WA 98004
Open in Google Maps ↗

Other Identifiers 1

Medicaid1089427WA

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Premera Blue Cross Blue Shield of Alaska, Providence Health Plan.Insurance ›

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Mary Dawn Sienkiewicz Arnp is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignment

Medicare enrollment records show Mary Sienkiewicz reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

The Association Of University Physicians
6.9 mi
Anesthesiology
701 5TH AVE, SUITE 700
Seattle, WA 98104
  • Reassigned Medicare billing, Washington enrollment
  • 4,364 clinicians in this Medicare group
NPI 1023041159 (206) 543-6420

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 98004 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$97.43 typical visit price
range $63.67 – $189.37
Typical copayment $24.35 (range $15.91 – $47.34)
Most-billed visit code 99203
Established Patient
$111.00 typical visit price
range $21.12 – $155.00
Typical copayment $27.75 (range $5.28 – $38.75)
Most-billed visit code 99214
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Medicare Quality Performance CMS QPP · MIPS

Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.

93.09/100
MIPS Final ScoreMerit-based Incentive Payment System · CMS Quality Payment Program
Scored through an Alternative Payment Model
Quality73.95
Promoting Interoperability100
Improvement Activities40

Other Providers at the Same Location NPPES 5

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

JENNIFER LEE BROWN-RAMOS ARNP
Nurse Practitioner (Women's Health)
1231 116TH AVE NE STE 950
BELLEVUE, WA 98004
King County (425) 454-3366
DR. SARAH LINSE BIENENFELD M.D.
Obstetrics & Gynecology
1231 116TH AVE NE STE 950
BELLEVUE, WA 98004
King County (425) 454-6674
MS. JEMMA NONOG ARNP, CNM
Advanced Practice Midwife
1231 116TH AVE NE STE 950
BELLEVUE, WA 98004
King County (425) 454-3366
DR. MEGAN CRENSHAW MD
Obstetrics & Gynecology
1231 116TH AVE NE STE 950
BELLEVUE, WA 98004
King County (425) 454-3366
JEAN E CHAKRABORTY MD
Obstetrics & Gynecology
1231 116TH AVE NE STE 950
BELLEVUE, WA 98004
King County (425) 454-3366

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Mary Sienkiewicz's NPI number?

The NPI number for Mary Sienkiewicz is 1245413533. It was assigned to this individual provider in the NPPES registry on December 10, 2007.

Where is Mary Sienkiewicz located?

Mary Sienkiewicz practices at 1231 116th Ave NE Ste 950, Bellevue, WA 98004. The listed phone number is (206) 328-7734.

What is Mary Sienkiewicz's specialty?

The primary specialty registered for this NPI is Nurse Practitioner with taxonomy code 363L00000X.

Is Mary Sienkiewicz enrolled in Medicare?

Yes. Mary Sienkiewicz is registered in the Medicare PECOS enrollment system.

Which organization bills Medicare for Mary Sienkiewicz's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Mary Sienkiewicz reassigns Medicare benefits to The Association Of University Physicians (Seattle, WA). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Mary Sienkiewicz's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

What insurance does Mary Sienkiewicz accept?

Health plans from Premera Blue Cross Blue Shield of Alaska and Providence Health Plan list Mary Sienkiewicz as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.

When was this NPI record last updated?

The NPPES record for Mary Sienkiewicz was last updated on November 29, 2018. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 7 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.