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DR. MARY MICHAEL WESTERHOLM M.D.
NPI 1790951093
Internal Medicine in Winfield, IL

Active since May 06, 2008PECOS EnrolledAccepts Medicare Assignment
25 N WINFIELD RD, WINFIELD, IL 60190(630) 653-0848(630) 653-7746 Get Directions Write a Review

NPPES record last updated: April 15, 2013. Verified against the NPPES registry weekly; last sync: October 18, 2026.

About Dr. Mary Michael Westerholm M.d. NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

DR. MARY MICHAEL WESTERHOLM M.D. (NPI 1790951093) is an individual internal medicine provider in Winfield, Illinois, licensed in Illinois (036116854) and active in the NPI registry since May 2008. She is enrolled in Medicare PECOS and is a graduate of Loyola University Of Chicago, Stritch School Of Medicine (2004).

NPPES Registry Identity

NPI1790951093
Entity TypeIndividualFemale
Primary Taxonomy207R00000X
Provider Legal NameDR. MARY MICHAEL WESTERHOLMCredential: M.D.
Location Address25 N WINFIELD RDWinfield, IL 60190-1222
Mailing Address25 N Winfield RdWinfield, IL 60190-1222 · (630) 653-0848 · Fax (630) 653-7746
Phone(630) 653-0848
Fax(630) 653-7746
Sole ProprietorNo
Medical School CMSLoyola University Of Chicago, Stritch School Of MedicineGraduated 2004
Enumeration DateMay 6, 2008
Last NPPES UpdateApril 15, 2013
✔ NPI 1790951093 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207R00000X
License✔ Licensed in IL · 036116854
Definition
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
Also ListedPediatricsTaxonomy 208000000X · License 036116854 (IL)
25 N WINFIELD RD, Winfield, IL 60190
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Other Identifiers 7

Other363149833IL · Tax Identification Number
Other3631498336019001IL · Cdpg Hfs Payee Id
Medicare PINK53640IL
Medicaid036116854IL
Other487450IL · Medicare Group Number
Other0222075IL · Blue Cross Group Number
OtherP00659358IL · Medicare Railroad

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Ambetter Health, Ambetter Health of Delaware.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

Dr. Mary Michael Westerholm M.d. 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.

PECOS PAC ID4880752609
PECOS Enrollment IDI20081023000375
Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignments

2

Medicare enrollment records show Mary Westerholm reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Central Dupage Physician Group
4.2 mi
Family Medicine
5777 DEPARTMENT
Carol Stream, IL 60122
  • Reassigned Medicare billing, Illinois enrollment
  • 1,664 clinicians in this Medicare group
NPI 1033149844 (630) 933-3300
Lawndale Christian Health Center
23 mi
Federally Qualified Health Center (FQHC)
3860 W OGDEN AVE
Chicago, IL 60623
  • Reassigned Medicare billing, Illinois enrollment
  • 147 clinicians in this Medicare group
NPI 1245289214 (773) 843-2705

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 60190 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$137.43 typical visit price
range $59.81 – $181.38
Typical copayment $34.35 (range $14.95 – $45.34)
Most-billed visit code 99204
Established Patient
$105.07 typical visit price
range $19.15 – $147.12
Typical copayment $26.26 (range $4.78 – $36.78)
Most-billed visit code 99214
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

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.

JOSEPH RAYMOND SCHNEIDER MD
Surgery (Vascular Surgery)
25 N WINFIELD RD, SUITE 201
WINFIELD, IL 60190
Dupage County (630) 933-4487
JESSICA LASAK BERNARDI APN
Nurse Practitioner
25 N WINFIELD RD
WINFIELD, IL 60190
Dupage County (630) 933-2157
KAITLYNN HARPER
Speech-Language Pathologist
25 N WINFIELD RD
WINFIELD, IL 60190
Dupage County (630) 933-1500
DR. TIMOTHY J MCGEE DO
Internal Medicine (Pulmonary Disease)
25 N WINFIELD RD
WINFIELD, IL 60190
Dupage County (630) 690-4553
DR. RANDY S WITTMAN MD
Obstetrics & Gynecology
25 N WINFIELD RD
WINFIELD, IL 60190
Dupage County (630) 653-4240
DR. KIRK JAMES PAPA M.D.
Anesthesiology
25 N WINFIELD RD
WINFIELD, IL 60190
Dupage County (630) 933-6675
SETH T KAY M.D.
Otolaryngology
25 N WINFIELD RD
WINFIELD, IL 60190
Dupage County (630) 933-6879
KRISTEN FLUBACKER FNP-C
Nurse Practitioner (Family)
25 N WINFIELD RD
WINFIELD, IL 60190
Dupage County (630) 933-1600

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 Westerholm's NPI number?

The NPI number for Mary Westerholm is 1790951093. It was assigned to this individual provider in the NPPES registry on May 6, 2008.

Where is Mary Westerholm located?

Mary Westerholm practices at 25 N Winfield Rd, Winfield, IL 60190. The listed phone number is (630) 653-0848.

What is Mary Westerholm's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Is Mary Westerholm enrolled in Medicare?

Yes. Mary Westerholm 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 Westerholm's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Mary Westerholm reassigns Medicare benefits to 2 organizations: Central Dupage Physician Group (Carol Stream, IL) and Lawndale Christian Health Center (Chicago, IL). 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 Westerholm's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

What insurance does Mary Westerholm accept?

Health plans from Ambetter Health and Ambetter Health of Delaware list Mary Westerholm 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 Mary Westerholm was last updated on April 15, 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.