Doctor profile · Federal record

Dr. Daniel Grzegorek, D.O.

Internal Medicine Physician (CMS: Internal Medicine) · Willowbrook, IL

  • NPI 1487651337
  • Accepts Medicare
  • 34 yrs in practice
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
6733 Kingery Hwy
Willowbrook, IL 605275142
(630) 325-4049
Mailing address
Po Box 713260
Chicago, IL 606771260

Credentials & registration

NPPES · NUCC
NPI registered
July 2005 — 21 yrs on file
Profile last updated
August 8, 2023
Year of graduation
1992 — 34 yrs since
Specialty taxonomy
207R00000X — NUCC code
State license (1)
Illinois #036-089211
Medicaid
IL #036089211

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1487651337. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
4,918
Distinct HCPCS
10
Medicare allowed
$318,251
HCPCS Description Services Patients Avg allowed
99308 Subsequent nursing facility care with straightforward level of medical decision making, per day, if using time, at least 15 minutes 549 213 $77
36415 Insertion of needle into vein for collection of blood sample 520 328 $8
99214 Established patient office or other outpatient visit, 30-39 minutes 491 285 $133
80053 Blood test, comprehensive group of blood chemicals 417 310 $10
84443 Blood test, thyroid stimulating hormone (tsh) 330 288 $16
80061 Blood test, lipids (cholesterol and triglycerides) 317 282 $13
99306 Initial nursing facility care with high level of medical decision making, per day, if using time, at least 45 minutes 316 279 $187
99309 Subsequent nursing facility care with moderate level of medical decision making, per day, if using time, at least 30 minutes 306 168 $110
85025 Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count 288 259 $8
G0439 Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit 283 283 $133

In context: peer comparison

Among 2 peers in Willowbrook Internal Medicine Physician, average services per provider: 119. This provider delivers 41× the peer median.

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
4,505
Patients
1,287
Total drug cost
$187,857
Drug Type Claims Patients Total cost
Atorvastatin Calcium Generic 685 198 $9,757
Levothyroxine Sodium Generic 552 153 $9,719
Amlodipine Besylate Generic 398 114 $4,290
Simvastatin Generic 344 94 $3,929
Lisinopril Generic 298 90 $3,404
Losartan Potassium Generic 292 80 $4,138
Metformin Hcl Generic 266 82 $2,701
Eliquis (Apixaban) Brand 257 53 $128,944
Gabapentin Generic 249 81 $4,061
Metoprolol Succinate Generic 222 72 $3,960

Frequently asked questions

Auto-generated from federal data
What is Dr. Daniel Grzegorek's medical specialty?
Dr. Daniel Grzegorek practices Internal Medicine Physician in Willowbrook, IL.
Where does Dr. Daniel Grzegorek practice?
Dr. Daniel Grzegorek practices at 6733 Kingery Hwy, Willowbrook, IL 605275142. Office phone: 6303254049.
What is Dr. Daniel Grzegorek's NPI?
Dr. Daniel Grzegorek's National Provider Identifier (NPI) is 1487651337, issued by NPPES.
Does Dr. Daniel Grzegorek accept Medicare assignment?
Yes. Dr. Daniel Grzegorek accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Daniel Grzegorek commonly perform?
Top Medicare-reported procedures in 2023: Subsequent nursing facility care with straightforward level of medical decision making (HCPCS 99308); Insertion of needle into vein for collection of blood sample (HCPCS 36415); Established patient office or other outpatient visit (HCPCS 99214). Source: CMS Medicare Physician & Other Practitioners file.