MRS. KAREN JANET TERWILLIGER MS, APRN, AGPCNP-BC
NPI 1245616705
Nurse Practitioner - Gerontology in Mystic, CT
About Mrs. Karen Janet Terwilliger Ms, Aprn, Agpcnp-bc NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MRS. KAREN JANET TERWILLIGER MS, APRN, AGPCNP-BC (NPI 1245616705) is an individual gerontology provider in Mystic, Connecticut, licensed in Connecticut (6220) and active in the NPI registry since August 2015. She is enrolled in Medicare PECOS, maintains 2 additional practice locations, and is a graduate of Other (2015).
NPPES Registry Identity
Specialties & Licenses 2
Secondary Practice Locations 2
Accepted Insurance
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
Mrs. Karen Janet Terwilliger Ms, Aprn, Agpcnp-bc 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 Karen Terwilliger reassigns Medicare billing to 3 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Norwich, CT 06360
- Reassigned Medicare billing, Connecticut enrollment
- 430 clinicians in this Medicare group
Willimantic, CT 06226
- Reassigned Medicare billing, Connecticut enrollment
- 302 clinicians in this Medicare group
Southport, CT 06890
- Reassigned Medicare billing, Connecticut enrollment
- 11 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 9
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.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 06355 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 7
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
MYSTIC, CT 06355
MYSTIC, CT 06355
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 Karen Terwilliger's NPI number?
The NPI number for Karen Terwilliger is 1245616705. It was assigned to this individual provider in the NPPES registry on August 7, 2015.
Where is Karen Terwilliger located?
Karen Terwilliger practices at 3 Heron Rd, Mystic, CT 06355. The listed phone number is (401) 497-6799.
What is Karen Terwilliger's specialty?
The primary specialty registered for this NPI is Nurse Practitioner, specializing in Gerontology, with taxonomy code 363LG0600X.
Is Karen Terwilliger enrolled in Medicare?
Yes. Karen Terwilliger 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 Karen Terwilliger's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Karen Terwilliger reassigns Medicare benefits to 3 organizations: The William W Backus Hospital (Norwich, CT), Windham Community Memorial Hospital, Inc. (Willimantic, CT) and Integrated Wound Care Connecticut PLLC (Southport, CT). 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 Karen Terwilliger's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Karen Terwilliger accept?
Health plans from Anthem Blue Cross and Blue Shield list Karen Terwilliger 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 Karen Terwilliger was last updated on June 2, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 5 months 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.
# Mrs. Karen Janet Terwilliger, MS, APRN, AGPCNP-BC · NPI 1245616705
Gerontology physician in Mystic, Connecticut. Individual provider, active in the CMS NPPES registry since August 7, 2015.
## Identity
- **NPI:** 1245616705 (Entity type: Individual)
- **Enumerated:** August 7, 2015
- **Primary specialty:** Nurse Practitioner - Gerontology · taxonomy 363LG0600X
- **State license:** 6220 (Connecticut)
- **Sole proprietor:** No
## Practice location
- **Address:** 3 HERON RD, Mystic, CT 06355-3253
- **Phone:** (401) 497-6799
## 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): The William W Backus Hospital (NPI 1467517235, Norwich, CT); Windham Community Memorial Hospital, Inc. (NPI 1023191467, Willimantic, CT); Integrated Wound Care Connecticut PLLC (NPI 1649778762, Southport, CT) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2015
## Record status
- **NPPES last updated:** June 2, 2026
---
Source: [NPI Profile](https://npiprofile.com/npi/1245616705) · Data from the CMS NPPES public registry.