Michael Grzelak, M.D.
NPI 1386808913 · Hospitalist Physician · Winfield, IL
Enrolled with Medicare as Practitioner - Hospitalist · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Michael Grzelak, M.D. is a Hospitalist Physician provider in Winfield, IL (NPI 1386808913).
Provider details
- NPI number
- 1386808913
- Entity type
- Individual
- Primary specialty
- Hospitalist PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- 036124898 (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 tenure28% of score
17 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
905 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) |
|---|---|---|
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 50 Minutes99233 | 374 | $124 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 251 | $82 |
| Hospital Discharge Day Management, More Than 30 Minutes99239 | 138 | $119 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 94 | $180 |
| Hospital Discharge Day Management, 30 Minutes Or Less99238 | 18 | $85 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2008-07-14
- Last updated
- 2018-01-18
Frequently asked questions
- What is Michael Grzelak's NPI number?
- Michael Grzelak's National Provider Identifier (NPI) is 1386808913, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Michael Grzelak's specialty?
- Michael Grzelak is listed in the NPPES registry with a primary specialty of Hospitalist Physician (Allopathic & Osteopathic Physicians).
- Where is Michael Grzelak located?
- Michael Grzelak's practice location on file with NPPES is 25 N Winfield Rd, Winfield, IL 60190-1295.
- What is Michael Grzelak's phone number?
- The practice phone number listed in the NPPES registry for Michael Grzelak is (630) 933-4700.
- Does Michael Grzelak accept Medicare?
- Michael Grzelak is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Michael Grzelak's NPI active?
- Yes — Michael Grzelak's NPI (1386808913) is active in the NPPES registry as of the last update on 2018-01-18.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.