Daniel Grzegorek, D.O.
NPI 1487651337 · Internal Medicine Physician · Willowbrook, IL
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Daniel Grzegorek, D.O. is a Internal Medicine Physician provider in Willowbrook, IL (NPI 1487651337).
Provider details
- NPI number
- 1487651337
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- D.O.
- Sex
- Male
- Sole proprietor
- No
- License
- 036-089211 (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
20 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
5,347 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) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 591 | $131 |
| Insertion of Needle Into Vein for Collection of Blood Sample36415 | 561 | $9 |
| Blood Test, Comprehensive Group of Blood Chemicals80053 | 465 | $10 |
| Subsequent Nursing Facility Care With Straightforward Level of Medical Decision Making, Per Day, If Using Time, 20 Minutes Or More99308 | 428 | $76 |
| 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 | 366 | $17 |
| Blood Test, Thyroid Stimulating Hormone (tsh) |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 151 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 786 | 203 |
| Levothyroxine Sodium | 607 | 169 |
| Amlodipine Besylate | 476 | 113 |
| Lisinopril | 388 | 90 |
| Losartan Potassium | 340 | 92 |
| Simvastatin | 334 | 97 |
| Gabapentin | 316 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2005-07-07
- Last updated
- 2023-08-08
- Certified
- 2023-08-08
Frequently asked questions
- What is Daniel Grzegorek's NPI number?
- Daniel Grzegorek's National Provider Identifier (NPI) is 1487651337, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Daniel Grzegorek's specialty?
- Daniel Grzegorek is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Daniel Grzegorek located?
- Daniel Grzegorek's practice location on file with NPPES is 6733 Kingery Hwy, Willowbrook, IL 60527-5142.
- What is Daniel Grzegorek's phone number?
- The practice phone number listed in the NPPES registry for Daniel Grzegorek is (630) 325-4049.
- Does Daniel Grzegorek accept Medicare?
- Daniel Grzegorek is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Daniel Grzegorek's NPI active?
- Yes — Daniel Grzegorek's NPI (1487651337) is active in the NPPES registry as of the last update on 2023-08-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.