Margaret Mcmahon, MD
NPI 1851366900 · Internal Medicine Physician · Maywood, IL
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Margaret Mcmahon, MD is a Internal Medicine Physician provider in Maywood, IL (NPI 1851366900).
Provider details
- NPI number
- 1851366900
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- 36095051 (IL)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
20 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
1,150 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. 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 .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 553 | $98 |
| Visit Complexity Inherent to Evaluation and Management Associated With Medical Care Services That Serve As the Continuing Focal Point for All Needed Health Care Services And/Or With Medical Care Services That Are Part of Ongoing Care Related to a Patient'SG2211 | 252 | $17 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 196 | $133 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 81 | $147 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 57 | $66 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 105 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 459 | 132 |
| Amlodipine Besylate | 440 | 121 |
| Rosuvastatin Calcium | 421 | 135 |
| Levothyroxine Sodium | 370 | 92 |
| Losartan Potassium | 327 | 91 |
| Lisinopril | 176 | 48 |
| Alendronate Sodium |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$71 across 1 record (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-02-22
- Last updated
- 2022-02-02
- Certified
- 2022-02-02
Frequently asked questions
- What is Margaret Mcmahon's NPI number?
- Margaret Mcmahon's National Provider Identifier (NPI) is 1851366900, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Margaret Mcmahon's specialty?
- Margaret Mcmahon is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Margaret Mcmahon located?
- Margaret Mcmahon's practice location on file with NPPES is 2160 S First Ave, Maywood, IL 60153.
- What is Margaret Mcmahon's phone number?
- The practice phone number listed in the NPPES registry for Margaret Mcmahon is (708) 327-7030.
- Does Margaret Mcmahon accept Medicare?
- Margaret Mcmahon is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Margaret Mcmahon's NPI active?
- Yes — Margaret Mcmahon's NPI (1851366900) is active in the NPPES registry as of the last update on 2022-02-02.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.