Dr. Daniel J Grzegorek , DO
Internal Medicine • Willowbrook, IL
6733 Kingery Hwy
Willowbrook, IL 605275142
This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.
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Dr. Daniel Grzegorek is listed in NPPES under Internal Medicine.
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NPI assigned on July 7, 2005; this date does not establish years in practice.
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Published CMS data list 5,431 Original Medicare Part B services in 2024.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024. Published rows only; this is not a quality measure.
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Published Part B service records, 2024:
- 99214 — Established patient outpatient office visit: 591 service units.
- 36415 — Insertion of needle into vein for collection of blood sample: 561 service units.
- 80053 — Blood test, comprehensive group of blood chemicals: 465 service units.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024. Units differ by code; these are not visits or a measure of quality.
CPT® only copyright 2023 American Medical Association. All rights reserved. Service names are shortened from CPT Consumer Friendly Descriptors (CMS data, 2024). CPT notice
See all 34 records in the table · Guide: How to read Medicare Part B data
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Published CMS data list 10,723 Medicare Part D prescriptions, including refills, in 2024.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2024. Published rows only; this is not a quality measure.
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Published Part D records, 2024:
- Atorvastatin Calcium — 786 prescription fills, including refills.
- Levothyroxine Sodium — 607 prescription fills, including refills.
- Amlodipine Besylate — 476 prescription fills, including refills.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2024. Drug names come from pharmacy claims. Listing a drug here is not an endorsement or a recommendation.
See all 151 records in the table · Guide: How to read Medicare Part D prescriber data
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More Medicare Part B services than 95% of clinicians listed under Internal Medicine in Illinois (2024, 3,249 clinicians with data). Median for this group: 699. Middle half: 285 to 1,340.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024. Billing and prescribing volume is not a quality rating.
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Medicare Part B services went from 4,027 in 2020 to 5,431 in 2024.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2020–2024.
Practice Location & Contact Primary Location
6733 Kingery Hwy
Willowbrook, IL 605275142
Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.
CMS Doctors and Clinicians lists 1 group name: Dupage Medical Group Ltd. See the list
Source: CMS Doctors and Clinicians National Downloadable File, release date unavailable.
Listings do not confirm current availability, employment or a shared ownership network.
Medicare Profile & Education
Source: CMS Doctors and Clinicians National Downloadable File
Chicago College Of Osteopathy
1992
What Public CMS Data Show
Internal Medicine: NPPES taxonomy is a reported classification, not proof of board certification.
Medicare patients
641 people with Original Medicare in 2024
It gives a sense of how many people with Medicare this clinician treated that year.
Source: CMS, Medicare Physician & Other Practitioners – by Provider, 2024.
Medicare-allowed amount
About $312,706 in 2024
The total amount Medicare approved for these services in 2024. It includes what Medicare paid and what patients or their other insurance owed, such as the deductible and coinsurance.
It shows the total cost of this clinician's Original Medicare services under Medicare's fee rules.
What this does not show: Medicare-allowed amount
This is not the clinician's income. Part of it can go to a clinic or group practice, staff, equipment or drugs. It is not the price you will pay.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024.
Paid by Medicare
About $253,994 in 2024
The part of the Medicare-allowed amount that Medicare itself paid in 2024, after patients' deductibles and coinsurance.
The gap between the allowed amount and this number is roughly what patients and their other insurance paid.
What this does not show: Paid by Medicare
This is not the clinician's income and not a measure of quality.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024.
30-day fills
21,890 standardized 30-day fills in 2024
CMS converts prescriptions to 30-day supplies so they can be compared. A 90-day prescription counts as about three 30-day fills.
What this does not show: 30-day fills
It is not a count of patients and not a measure of quality.
Part D drug cost
$479,311 in 2024
The total cost of these prescriptions in 2024, paid by Medicare drug plans, patients and other payers together.
It shows the total spending on drugs this clinician prescribed, not what any one patient paid.
What this does not show: Part D drug cost
A higher cost often reflects the type of medicines a specialty uses. It is not your out-of-pocket cost and not a measure of quality.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2024.
Industry payments (Open Payments)
Fewer than 11 payment records totaling $20.61 in 2022
Drug and medical device companies must report certain payments to doctors and some other clinicians to CMS, such as meals, travel, speaking fees or research funding.
It shows reported financial ties between this clinician and companies. You can ask your clinician about them.
These records are submitted by drug and medical device companies, and a reported payment does not necessarily mean the financial relationship is improper.
General: payments not tied to research, such as meals, travel, consulting or speaking fees.
A reported payment does not necessarily mean the financial relationship is improper. Research payments can go to a hospital or university for a study the clinician leads, not to the clinician personally. Clinicians can dispute records with the company that reported them.
Source: CMS Open Payments, program year 2022.
Years since graduation
34 years (graduated 1992)
CMS Doctors and Clinicians data list 1992 as the year this clinician finished professional school.
It tells you roughly how long ago the clinician finished school.
What this does not show: Years since graduation
It is not the number of years in practice, and more years does not mean better care.
Source: CMS Doctors and Clinicians National Downloadable File.
NPI first issued
2005
The year this clinician's National Provider Identifier (NPI) was issued. An NPI is a unique 10-digit ID that US health care providers use for billing.
What this does not show: NPI first issued
NPIs have been issued only since 2005, so this year is not necessarily when the clinician started practicing.
Source: CMS NPPES NPI Registry.
Accepts Medicare assignment
CMS data list this clinician as accepting Medicare assignment. This means agreeing to take the Medicare-approved amount as full payment for covered services.
With Original Medicare, you usually pay only your deductible and coinsurance, and the office sends the claim to Medicare for you.
Medicare assignment applies to Original Medicare. It does not tell you whether the clinician is in a Medicare Advantage plan's network, accepts other insurance, or is taking new patients.
Source: CMS Doctors and Clinicians; Medicare.gov, “Does your provider accept Medicare as full payment?”
Telehealth (some services)
Recent Medicare claims show this clinician provided some services by telehealth, such as a video or phone visit.
You may be able to have some visits without going to the office. Ask which visits can be done by telehealth.
What this does not show: Telehealth (some services)
It does not mean all services are offered by telehealth, or that telehealth is covered by your plan.
Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians.
Enrolled in Medicare (PECOS)
Dr. Grzegorek has a Medicare enrollment record in PECOS, the CMS system clinicians use to enroll so they can bill Medicare or order services for people with Medicare.
It does not show whether the clinician accepts assignment, is in your plan's network, or is taking new patients.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Can order Medicare-covered services
CMS lists Dr. Grzegorek as eligible to order or refer Medicare Part B clinical laboratory and imaging services, durable medical equipment (DME) and home health services for people with Medicare.
Medicare pays for these items and services only when they are ordered by an eligible clinician.
What this does not show: Can order Medicare-covered services
It does not mean the clinician offers these services directly.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Compared with the same specialty in Willowbrook and Illinois
Billing and prescribing volume is not a quality rating.
Medicare Part B services
More Medicare Part B services than 95% of clinicians listed under Internal Medicine in Illinois (2024, 3,249 clinicians with data). Median for this group: 699. Middle half: 285 to 1,340.
Too few clinicians listed under Internal Medicine in Willowbrook have Medicare Part B data for 2024 to compare.
Medicare-allowed amount
A higher Medicare-allowed amount than 95% of clinicians listed under Internal Medicine in Illinois (2024, 3,249 clinicians with data). Median for this group: $67,802. Middle half: $27,619 to $124,679.
Too few clinicians listed under Internal Medicine in Willowbrook have Medicare Part B data for 2024 to compare.
Paid by Medicare
A higher Medicare payment amount than 95% of clinicians listed under Internal Medicine in Illinois (2024, 3,249 clinicians with data). Median for this group: $52,838. Middle half: $21,117 to $98,214.
Too few clinicians listed under Internal Medicine in Willowbrook have Medicare Part B data for 2024 to compare.
Medicare Part D prescriptions
More Part D prescriptions than 90% of clinicians listed under Internal Medicine in Illinois (2024, 3,755 clinicians with data). Median for this group: 1,030. Middle half: 99 to 4,658.
Too few clinicians listed under Internal Medicine in Willowbrook have Medicare Part D data for 2024 to compare.
Part D drug cost
A higher Part D drug cost than 80% of clinicians listed under Internal Medicine in Illinois (2024, 3,755 clinicians with data). Median for this group: $78,716. Middle half: $2,604 to $371,507.
Too few clinicians listed under Internal Medicine in Willowbrook have Medicare Part D data for 2024 to compare.
7 active clinicians are listed under Internal Medicine with a practice address in Willowbrook, IL (7,245 in Illinois).
Addresses are self-reported to NPPES and may be out of date.
CMS data by year
Changes may reflect reporting, coverage or privacy limits, not changes in care quality.
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Medicare Part B services
Medicare Part B services increased 35% from 4,027 in 2020 to 5,431 in 2024.
- 2020: 4,027
- 2021: 5,058
- 2022: 4,958
- 2023: 4,918
- 2024: 5,431
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Medicare-allowed amount
Medicare-allowed amount increased 32% from $237,473 in 2020 to $312,706 in 2024.
- 2020: $237,473
- 2021: $310,262
- 2022: $307,984
- 2023: $318,246
- 2024: $312,706
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Paid by Medicare
Paid by Medicare increased 31% from $193,692 in 2020 to $253,994 in 2024.
- 2020: $193,692
- 2021: $249,384
- 2022: $245,781
- 2023: $255,697
- 2024: $253,994
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Medicare Part D prescriptions
Medicare Part D prescriptions increased 91% from 5,605 in 2020 to 10,723 in 2024.
- 2020: 5,605
- 2021: 7,009
- 2022: 8,483
- 2023: 9,750
- 2024: 10,723
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30-day fills
30-day fills increased 76% from 12,431 in 2020 to 21,890 in 2024.
- 2020: 12,431
- 2021: 15,097
- 2022: 17,383
- 2023: 19,741
- 2024: 21,890
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Part D drug cost
Part D drug cost increased 101% from $238,257 in 2020 to $479,311 in 2024.
- 2020: $238,257
- 2021: $279,162
- 2022: $375,584
- 2023: $461,105
- 2024: $479,311
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Industry payments (Open Payments)
Industry payments (Open Payments) went from $143.85 in 2019 to $20.61 in 2022.
- 2019: $143.85
- 2020: $83.70
- 2021: $33.34
- 2022: $20.61
Sources: CMS Medicare Physician & Other Practitioners (2024), CMS Medicare Part D Prescribers (2024), CMS Open Payments (2022), CMS Doctors and Clinicians, CMS NPPES NPI Registry. Specialty names follow the NUCC Health Care Provider Taxonomy.
Text: T-MedInfo · Report an error.
Pharma & Medical Device Financial Disclosures
Payments and other transfers of value that drug and medical device companies reported to CMS Open Payments
Program year 2022 (payments made January 1 – December 31, 2022): fewer than 11 records totaling $20.61.
| Manufacturer | Payment Nature | Product | Type | Amount ($) |
|---|---|---|---|---|
| ACADIA Pharmaceuticals Inc |
Food and Beverage
In-kind items and services
|
NUPLAZID | General | $20.61 |
Source: CMS Open Payments, program year 2022, released June 30, 2026.
Performed Procedures & Service Volume
CPT® is a registered trademark of the American Medical Association. CPT codes, descriptions and other data only are copyright 2016–2023 American Medical Association. All rights reserved. Applicable FARS/HHSARS apply. Descriptions of CPT codes are the AMA's CPT Consumer Friendly Descriptors as published by CMS in the Medicare Physician & Other Practitioners – by Provider and Service data, 2017–2024; they are plain-language summaries, not for clinical coding or documentation. HCPCS Level II codes and descriptions are from CMS. Fee schedules, relative value units, conversion factors and/or related components are not assigned by the AMA, are not part of CPT, and the AMA is not recommending their use. The AMA does not directly or indirectly practice medicine or dispense medical services. The AMA assumes no liability for data contained or not contained herein.
| HCPCS Code | Services | Patients | Submitted Charge | Medicare Allowed |
|---|---|---|---|---|
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99214
Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more
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591 | 307 | $229.00 | $130.97 |
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36415
Insertion of needle into vein for collection of blood sample
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561 | 349 | $20.00 | $8.62 |
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80053
Blood test, comprehensive group of blood chemicals
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465 | 329 | $55.00 | $10.31 |
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99308
Subsequent nursing facility care with straightforward level of medical decision making, per day, if using time, 20 minutes or more
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428 | 146 | $146.00 | $75.71 |
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G2211
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's
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366 | 239 | $35.00 | $16.72 |
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84443
Blood test, thyroid stimulating hormone (tsh)
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364 | 321 | $86.00 | $16.42 |
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85025
Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count
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353 | 299 | $40.00 | $7.61 |
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80061
Blood test, lipids (cholesterol and triglycerides)
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352 | 317 | $69.00 | $13.09 |
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G0439
Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit
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326 | 326 | $229.00 | $132.87 |
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99309
Subsequent nursing facility care with moderate level of medical decision making, per day, if using time, at least 30 minutes
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264 | 118 | $190.00 | $109.58 |
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99306
Initial nursing facility care with high level of medical decision making, per day, if using time, 50 minutes or more
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209 | 184 | $357.00 | $184.37 |
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99213
Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more
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202 | 156 | $157.00 | $93.27 |
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83036
Hemoglobin a1c level
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171 | 89 | $50.00 | $9.52 |
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82570
Creatinine level to test for kidney function or muscle injury
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86 | 72 | $27.00 | $5.08 |
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82043
Urine microalbumin (protein) level
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83 | 70 | $30.00 | $5.66 |
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99308
Subsequent nursing facility care with straightforward level of medical decision making, per day, if using time, 20 minutes or more
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83 | 27 | $146.00 | $75.79 |
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G0103
Prostate cancer screening; prostate specific antigen test (psa)
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68 | 68 | $52.00 | $18.92 |
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G0008
Administration of influenza virus vaccine
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50 | 49 | $55.00 | $33.45 |
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90653
Influenza vaccine, inactivated
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45 | 45 | $251.00 | $81.82 |
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99315
Nursing facility discharge day management, 30 minutes or less
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45 | 44 | $154.00 | $82.98 |
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90677
Pneumococcal conjugate vaccine, 20 valent (pcv20), for intramuscular use
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39 | 39 | $851.00 | $291.14 |
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G0009
Administration of pneumococcal vaccine
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39 | 39 | $55.00 | $33.45 |
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80048
Blood test, basic group of blood chemicals (calcium, total)
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29 | 25 | $44.00 | $8.29 |
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99309
Subsequent nursing facility care with moderate level of medical decision making, per day, if using time, at least 30 minutes
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29 | 17 | $190.00 | $109.46 |
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99442
Telephone medical discussion with physician, 11-20 minutes
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28 | 20 | $179.00 | $92.82 |
(top 25 shown)
Source: CMS Part B by Provider and Service, 2024; services under 11 beneficiaries omitted by CMS. Privacy limits
Submitted charges are billed amounts, not a price quote for your visit.
Medicare Part D Prescribing Profile & Medications
Medicare Part D prescriptions filled, including refills, in 2024.
| Brand Name | Generic Name | Prescriptions | Day Supply | Total Cost | Patients |
|---|---|---|---|---|---|
| Atorvastatin Calcium | Atorvastatin Calcium | 786 | 53,764 | $9,013.88 | 203 |
| Levothyroxine Sodium | Levothyroxine Sodium | 607 | 46,533 | $8,618.47 | 169 |
| Amlodipine Besylate | Amlodipine Besylate | 476 | 29,490 | $3,939.41 | 113 |
| Lisinopril | Lisinopril | 388 | 26,708 | $3,496.32 | 90 |
| Losartan Potassium | Losartan Potassium | 340 | 23,001 | $4,458.24 | 92 |
| Simvastatin | Simvastatin | 334 | 27,402 | $3,027.42 | 97 |
| Gabapentin | Gabapentin | 316 | 12,437 | $4,273.92 | 86 |
| Metformin Hcl | Metformin Hcl | 310 | 23,268 | $2,680.53 | 87 |
| Metoprolol Succinate | Metoprolol Succinate | 309 | 19,739 | $4,208.83 | 94 |
| Eliquis | Apixaban | 257 | 6,706 | $134,265.59 | 44 |
| Rosuvastatin Calcium | Rosuvastatin Calcium | 217 | 14,724 | $3,075.92 | 64 |
| Pantoprazole Sodium | Pantoprazole Sodium | 214 | 11,901 | $3,653.73 | 54 |
| Tamsulosin Hcl | Tamsulosin Hcl | 199 | 13,534 | $2,551.00 | 61 |
| Carvedilol | Carvedilol | 195 | 11,004 | $3,240.06 | 48 |
| Omeprazole | Omeprazole | 173 | 11,135 | $1,846.30 | 47 |
| Metoprolol Tartrate | Metoprolol Tartrate | 169 | 9,050 | $1,343.30 | 45 |
| Furosemide | Furosemide | 164 | 7,914 | $1,017.31 | 51 |
| Hydrochlorothiazide | Hydrochlorothiazide | 146 | 12,448 | $940.75 | 45 |
| Trazodone Hcl | Trazodone Hcl | 139 | 8,168 | $1,230.45 | 33 |
| Memantine Hcl | Memantine Hcl | 139 | 4,031 | $4,474.00 | 24 |
| Clopidogrel | Clopidogrel Bisulfate | 136 | 6,772 | $1,858.27 | 35 |
| Potassium Chloride | Potassium Chloride | 133 | 7,268 | $2,568.02 | 39 |
| Donepezil Hcl | Donepezil Hcl | 130 | 5,884 | $1,901.65 | 25 |
| Allopurinol | Allopurinol | 126 | 9,274 | $1,203.43 | 42 |
| Alendronate Sodium | Alendronate Sodium | 113 | 7,307 | $1,634.91 | 28 |
(top 25 shown)
Source: CMS Part D by Provider and Drug, 2024; rows below 11 claims omitted by CMS; volume isn’t quality. Privacy limits
Specialties & License Numbers Reported to NPPES
Self-certified to NPPES: 2023-08-08NUCC Taxonomy Code: 207R00000X
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
Additional State Medicaid & Healthcare Payer Identifiers
Medicare (PECOS) Enrollment & Ordering Eligibility
Source: CMS PECOSPRACTITIONER - INTERNAL MEDICINE
I20040403000087
IL
0749273183
Sources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.
Medicare Group Practice Enrollments
Source: CMS Doctors and Clinicians National Downloadable File
Dupage Medical Group Ltd
40 S Clay St, Hinsdale, IL 605213257
Dupage Medical Group Ltd
430 Pennsylvania Ave, Glen Ellyn, IL 601374464
Phone: 6304699200
Dupage Medical Group Ltd
30 Stratford Dr, Bloomingdale, IL 601082201
Phone: 6308932210
Dupage Medical Group Ltd
430 Warrenville Rd, Lisle, IL 605321348
Phone: 6304326180
Dupage Medical Group Ltd
1325 N Meacham Rd, Schaumburg, IL 601734824
Phone: 6304699200
Dupage Medical Group Ltd
6733 Kingery Hwy, Willowbrook, IL 605275142
Phone: 6303254049
Dupage Medical Group Ltd
2100 Glenwood Ave, Joliet, IL 604355487
Phone: 8157252121
Dupage Medical Group Ltd
17495 La Grange Rd, Tinley Park, IL 604877581
Phone: 7082267000
Clinicians Sharing This Practice Address or Phone
Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.
Nurse Practitioner
Advanced Practice Registered Nurse, Family Nurse Practitioner (Certified)
Career & Practice History Timeline
Changes recorded in monthly NPPES data files: addresses, names, credentials, specialties and NPI status
Registered at PO BOX 713260, CHICAGO, IL 606771260 (Tel: 6304699200)
NPI status registered as active in NPPES database
Registered at 6733 KINGERY HWY, WILLOWBROOK, IL 605275142 (Tel: 6303254049)
Registered at 1860 PAYSPHERE CIR, CHICAGO, IL 606740001
Recorded as DANIEL GRZEGOREK, D.O.
Internal Medicine (license number reported to NPPES: IL 036-089211)
First registered as active Individual Practitioner in NPPES Database.
NPI Administrative Meta
Other Internal Medicine Providers in Willowbrook
Healthcare providers in WillowbrookMailing Address
Po Box 713260
Chicago, IL 606771260
Phone: 6304699200