MARY-STEWART WILLSIE D.O.
NPI 1780818377
Emergency Medicine in Newark, DE
About Mary-stewart Willsie D.o. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MARY-STEWART WILLSIE D.O. (NPI 1780818377) is an individual emergency medicine provider in Newark, Delaware, licensed in Delaware (C7-0004280) and active in the NPI registry since May 2009. She is enrolled in Medicare PECOS, is affiliated with Main Line Hospital Lankenau, and is a graduate of Kansas City University Of Physicians And Surgeons (2009).
NPPES Registry Identity
Specialties & Licenses
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Mary-stewart Willsie D.o. is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignments
3Medicare enrollment records show Mary-stewart Willsie reassigns Medicare billing to 3 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Glen Mills, PA 19342
- Reassigned Medicare billing, Pennsylvania enrollment
- 654 clinicians in this Medicare group
Newtown Square, PA 19073
- Reassigned Medicare billing, Pennsylvania enrollment
- 1,638 clinicians in this Medicare group
Langhorne, PA 19047
- Reassigned Medicare billing, Pennsylvania enrollment
- Medicare enrollment name: Emergency Care Services Of Pennsylvania PC
- 329 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims 12
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Hospital Affiliations CMS Care Compare
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Main Line Hospital Lankenau
Acute Care Hospitals · Wynnewood, PAPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 19718 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
NEWARK, DE 19718
NEWARK, DE 19718
NEWARK, DE 19718
NEWARK, DE 19718
NEWARK, DE 19718
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-stewart Willsie's NPI number?
The NPI number for Mary-stewart Willsie is 1780818377. It was assigned to this individual provider in the NPPES registry on May 11, 2009.
Where is Mary-stewart Willsie located?
Mary-stewart Willsie practices at 4755 Ogletown Stanton Rd, Newark, DE 19718. The listed phone number is (130) 273-3100.
What is Mary-stewart Willsie's specialty?
The primary specialty registered for this NPI is Emergency Medicine with taxonomy code 207P00000X.
Is Mary-stewart Willsie enrolled in Medicare?
Yes. Mary-stewart Willsie is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organizations bill Medicare for Mary-stewart Willsie's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Mary-stewart Willsie reassigns Medicare benefits to 3 organizations: Prospect Health Access Network, Inc. (Glen Mills, PA), Main Line Healthcare (Newtown Square, PA) and Emergency Care Services Of Pennsylvania, P.C. (Langhorne, PA). Each 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-stewart Willsie's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
Is Mary-stewart Willsie affiliated with any hospitals?
According to CMS data, Mary-stewart Willsie is affiliated with Main Line Hospital Lankenau.
When was this NPI record last updated?
The NPPES record for Mary-stewart Willsie was last updated on July 25, 2013. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 13 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.
# Mary-Stewart Willsie, D.O. · NPI 1780818377
Emergency Medicine physician in Newark, Delaware. Individual provider, active in the CMS NPPES registry since May 11, 2009.
## Identity
- **NPI:** 1780818377 (Entity type: Individual)
- **Enumerated:** May 11, 2009
- **Primary specialty:** Emergency Medicine · taxonomy 207P00000X
- **State license:** C7-0004280 (Delaware)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 4755 OGLETOWN STANTON RD, Newark, DE 19718-0001
- **Phone:** (130) 273-3100
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 3 organizations under Medicare reassignment (form CMS-855R): Prospect Health Access Network, Inc. (NPI 1083061006, Glen Mills, PA); Main Line Healthcare (NPI 1922077643, Newtown Square, PA); Emergency Care Services Of Pennsylvania, P.C. (NPI 1114955010, Langhorne, PA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Kansas City University Of Physicians And Surgeons, class of 2009
## Record status
- **NPPES last updated:** July 25, 2013
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Source: [NPI Profile](https://npiprofile.com/npi/1780818377) · Data from the CMS NPPES public registry.