Mary Mahieu, M.D.
NPI 1811218381 · Rheumatology Physician · Chicago, IL
Enrolled with Medicare as Practitioner - Rheumatology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mary Mahieu, M.D. is a Rheumatology Physician provider in Chicago, IL (NPI 1811218381).
Provider details
- NPI number
- 1811218381
- Entity type
- Individual
- Primary specialty
- Rheumatology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Female
- Sole proprietor
- Yes
- License
- 036131440 (IL)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
16 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
441 Medicare services, 2024 (ranked within specialty)
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 methodology.
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) |
|---|---|---|
| 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 | 199 | $17 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 135 | $133 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 78 | $186 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 17 | $95 |
| Initial Hospital Care With Straightforward Or Low-Level Medical Decision Making, If Using Time, at Least 55 Minutes99222 | 12 | $140 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 19 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Hydroxychloroquine Sulfate | 228 | 74 |
| Prednisone | 128 | 38 |
| Methotrexate Sodiumbrand: Methotrexate | 91 | 35 |
| Mycophenolate Mofetil | 35 | 12 |
| Azathioprine | 34 | — |
| Adalimumabbrand: Humira(cf) Pen | 34 | — |
| Colchicine | 31 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2010-06-18
- Last updated
- 2016-08-30
Frequently asked questions
- What is Mary Mahieu's NPI number?
- Mary Mahieu's National Provider Identifier (NPI) is 1811218381, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mary Mahieu's specialty?
- Mary Mahieu is listed in the NPPES registry with a primary specialty of Rheumatology Physician (Allopathic & Osteopathic Physicians).
- Where is Mary Mahieu located?
- Mary Mahieu's practice location on file with NPPES is 675 N Saint Clair St, Chicago, IL 60611-5975.
- What is Mary Mahieu's phone number?
- The practice phone number listed in the NPPES registry for Mary Mahieu is (312) 695-8628.
- Does Mary Mahieu accept Medicare?
- Mary Mahieu is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mary Mahieu's NPI active?
- Yes — Mary Mahieu's NPI (1811218381) is active in the NPPES registry as of the last update on 2016-08-30.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.