Margaret Grossmayer, APRN, FNP-C
NPI 1548140973 · Nurse Practitioner · Willowbrook, IL
Enrolled with Medicare as Practitioner - Nurse Practitioner · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Margaret Grossmayer, APRN, FNP-C is a Nurse Practitioner provider in Willowbrook, IL (NPI 1548140973).
Provider details
- NPI number
- 1548140973
- Entity type
- Individual
- Primary specialty
- Nurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- APRN, FNP-C
- Sex
- Female
- Sole proprietor
- Yes
- License
- 209033129 (IL)
Specialties & taxonomies
Physician Assistants & Advanced Practice Nursing Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
Under 1 yr in registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
Practice location
Mailing address
Registry dates
- Enumerated
- 2025-09-05
- Last updated
- 2025-11-26
- Certified
- 2025-11-26
Frequently asked questions
- What is Margaret Grossmayer's NPI number?
- Margaret Grossmayer's National Provider Identifier (NPI) is 1548140973, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Margaret Grossmayer's specialty?
- Margaret Grossmayer is listed in the NPPES registry with a primary specialty of Nurse Practitioner (Physician Assistants & Advanced Practice Nursing Providers).
- Where is Margaret Grossmayer located?
- Margaret Grossmayer's practice location on file with NPPES is 40 75th St, Willowbrook, IL 60527-2325.
- What is Margaret Grossmayer's phone number?
- The practice phone number listed in the NPPES registry for Margaret Grossmayer is (630) 581-5372.
- Does Margaret Grossmayer accept Medicare?
- Margaret Grossmayer is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Margaret Grossmayer's NPI active?
- Yes — Margaret Grossmayer's NPI (1548140973) is active in the NPPES registry as of the last update on 2025-11-26.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.