GRETCHEN K MATHEWSON FNP
NPI 1639494685
Nurse Practitioner - Family in New York, NY
About Gretchen K Mathewson Fnp NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
GRETCHEN K MATHEWSON FNP (NPI 1639494685) is an individual family provider in New York, New York, licensed in New York (F335831) and active in the NPI registry since April 2010. She is enrolled in Medicare PECOS, is affiliated with Mount Sinai Hospital, and is a graduate of Other (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
Gretchen K Mathewson Fnp 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
2Medicare enrollment records show Gretchen Mathewson reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Newyork, NY 10029
- Reassigned Medicare billing, New York enrollment
- 233 clinicians in this Medicare group
Bronx, NY 10471
- Reassigned Medicare billing, New York enrollment
- 21 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
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 2
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Mount Sinai Hospital
Acute Care Hospitals · New York, NYMount Sinai Beth Israel
Acute Care Hospitals · New York, NYPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 10029 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.
NEW YORK, NY 10029
NEW YORK, NY 10029
NEW YORK, NY 10029
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 Gretchen Mathewson's NPI number?
The NPI number for Gretchen Mathewson is 1639494685. It was assigned to this individual provider in the NPPES registry on April 1, 2010.
Where is Gretchen Mathewson located?
Gretchen Mathewson practices at 5 East 98th Street Box 1138, New York, NY 10029. The listed phone number is (212) 241-6854.
What is Gretchen Mathewson's specialty?
The primary specialty registered for this NPI is Nurse Practitioner, specializing in Family, with taxonomy code 363LF0000X.
Is Gretchen Mathewson enrolled in Medicare?
Yes. Gretchen Mathewson 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 Gretchen Mathewson's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Gretchen Mathewson reassigns Medicare benefits to 2 organizations: Icahn School Of Medicine At Mount Sinai (Newyork, NY) and Riverdale Mental Health Association Inc (Bronx, NY). 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 Gretchen Mathewson's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
Is Gretchen Mathewson affiliated with any hospitals?
According to CMS data, Gretchen Mathewson is affiliated with Mount Sinai Hospital and Mount Sinai Beth Israel.
When was this NPI record last updated?
The NPPES record for Gretchen Mathewson was last updated on October 25, 2010. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 15 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.
# Gretchen K Mathewson, FNP · NPI 1639494685
Family physician in New York, New York. Individual provider, active in the CMS NPPES registry since April 1, 2010.
## Identity
- **NPI:** 1639494685 (Entity type: Individual)
- **Enumerated:** April 1, 2010
- **Primary specialty:** Nurse Practitioner - Family · taxonomy 363LF0000X
- **State license:** F335831 (New York)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 5 EAST 98TH STREET, BOX 1138, New York, NY 10029-6501
- **Phone:** (212) 241-6854 · **Fax:** (212) 241-5333
## 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:** 2 organizations under Medicare reassignment (form CMS-855R): Icahn School Of Medicine At Mount Sinai (NPI 1558627844, Newyork, NY); Riverdale Mental Health Association Inc (NPI 1174557409, Bronx, NY) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2009
## Record status
- **NPPES last updated:** October 25, 2010
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Source: [NPI Profile](https://npiprofile.com/npi/1639494685) · Data from the CMS NPPES public registry.