MRS. MARGARET ESSEX CASTOR WHNP
NPI 1275960585
Nurse Practitioner - Women's Health in Phoenix, AZ
About Mrs. Margaret Essex Castor Whnp NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MRS. MARGARET ESSEX CASTOR WHNP (NPI 1275960585) is an individual women's health provider in Phoenix, Arizona, licensed in Arizona (300500) and active in the NPI registry since October 2013. She is enrolled in Medicare PECOS, maintains a secondary practice location in Phoenix, and is a graduate of Vanderbilt University School Of Medicine (2013).
NPPES Registry Identity
Specialties & Licenses 2
Secondary Practice Location 1
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. Margaret Essex Castor Whnp 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 Margaret Castor reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Tucson, AZ 85704
- Reassigned Medicare billing, Arizona enrollment
- 157 clinicians in this Medicare group
Carmel, IN 46032
- Reassigned Medicare billing, Indiana enrollment
- 135 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 2
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 85028 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 10
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
PHOENIX, AZ 85028
PHOENIX, AZ 85028
PHOENIX, AZ 85028
PHOENIX, AZ 85028
PHOENIX, AZ 85028
PHOENIX, AZ 85028
PHOENIX, AZ 85028
PHOENIX, AZ 85028
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 Margaret Castor's NPI number?
The NPI number for Margaret Castor is 1275960585. It was assigned to this individual provider in the NPPES registry on October 1, 2013.
Where is Margaret Castor located?
Margaret Castor practices at 11209 N Tatum Blvd Ste 255, Phoenix, AZ 85028. The listed phone number is (602) 494-5050.
What is Margaret Castor's specialty?
The primary specialty registered for this NPI is Nurse Practitioner, specializing in Women's Health, with taxonomy code 363LW0102X.
Is Margaret Castor enrolled in Medicare?
Yes. Margaret Castor 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 Margaret Castor's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Margaret Castor reassigns Medicare benefits to 2 organizations: Genesis Ob Gyn PLLC (Tucson, AZ) and Seven Hills Ob-Gyn Associates LLC (Carmel, IN). 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 Margaret Castor's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Margaret Castor accept?
Health plans from Blue Cross Blue Shield of Arizona, Cigna HealthCare of Arizona, Inc, Imperial Insurance Companies, Inc. and UnitedHealthcare list Margaret Castor 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 Margaret Castor was last updated on February 4, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 8 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. Margaret Essex Castor, WHNP · NPI 1275960585
Women's Health physician in Phoenix, Arizona. Individual provider, active in the CMS NPPES registry since October 1, 2013.
## Identity
- **NPI:** 1275960585 (Entity type: Individual)
- **Enumerated:** October 1, 2013
- **Primary specialty:** Nurse Practitioner - Women's Health · taxonomy 363LW0102X
- **State license:** 300500 (Arizona)
- **Sole proprietor:** No
## Practice location
- **Address:** 11209 N TATUM BLVD STE 255, Phoenix, AZ 85028-6061
- **Phone:** (602) 494-5050 · **Fax:** (866) 777-2251
## 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): Genesis Ob Gyn PLLC (NPI 1992994214, Tucson, AZ); Seven Hills Ob-Gyn Associates LLC (NPI 1396350187, Carmel, IN) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Vanderbilt University School Of Medicine, class of 2013
## Record status
- **NPPES last updated:** February 4, 2026
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Source: [NPI Profile](https://npiprofile.com/npi/1275960585) · Data from the CMS NPPES public registry.