Dr. Mary P Dea , DO
Internal Medicine • Naperville, IL
1804 N Naper Blvd, Ste 103
Naperville, IL 605638830
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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NPI assigned on September 7, 2005; this date does not establish years in practice.
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Published CMS data list 1,019 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: 198 service units.
- 36415 — Insertion of needle into vein for collection of blood sample: 167 service units.
- 99213 — Established patient outpatient office visit: 108 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 12 records in the table · Guide: How to read Medicare Part B data
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Published CMS data list 69 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:
- Tramadol Hcl — 17 prescription fills, including refills.
- Hydrocodone-Acetaminophen (Hydrocodone/Acetaminophen) — 15 prescription fills, including refills.
- Diazepam — 13 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 5 records in the table · Guide: How to read Medicare Part D prescriber data
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Close to the middle for Medicare Part B services among clinicians listed under Internal Medicine in Naperville, IL (2024, 57 clinicians with data). Median for this group: 1,193. Middle half: 679 to 2,128.
More Medicare Part B services than 65% of clinicians listed under Internal Medicine in Illinois (2024, 3,231 clinicians with data). Median for this group: 696. Middle half: 284 to 1,352.
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 759 in 2017 to 1,019 in 2024.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2017–2024.
Practice Location & Contact Primary Location
1804 N Naper Blvd
Ste 103
Naperville, IL 605638830
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: Health Service Systems, Inc. See the list
Source: CMS Doctors and Clinicians National Downloadable File, CMS release of October 2, 2026.
Listings do not confirm current availability, employment or a shared ownership network.
Medicare Profile & Education
Source: CMS Doctors and Clinicians National Downloadable File, CMS release of October 2, 2026
Midwestern University, Chicago College Of Osteopathic Med
1993
What Public CMS Data Show
Internal Medicine: NPPES taxonomy is a reported classification, not proof of board certification.
Medicare patients
232 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 $68,989 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 $57,105 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
85 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
$870 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.
Open Payments general payments, program year 2025
All general payments: $898.74 across 45 records.
By nature of payment
- Food and Beverage: $898.74 across 45 records.
Reporting-company totals (3 largest of 18)
- Novo Nordisk Inc: $133.45 across 7 records.
- Eli Lilly and Company: $101.83 across 5 records.
- Verity Pharmaceuticals Inc.: $95.64 across 4 records.
A reported payment does not necessarily mean the financial relationship is improper and is not a measure of care quality. Clinicians can review and dispute these records.
Source: Calculated by T-MedInfo from CMS Open Payments general-payment records for program year 2025 (published June 30, 2026).
Years since graduation
33 years (graduated 1993)
CMS Doctors and Clinicians data list 1993 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, CMS release of October 2, 2026.
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, CMS release of October 2, 2026; Medicare.gov, “Does your provider accept Medicare as full payment?”
No telehealth indicator
CMS shows this indicator only when recent Medicare claims include telehealth services. The clinician may still offer telehealth; ask the office.
Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians, CMS release of October 2, 2026.
Enrolled in Medicare (PECOS)
Dr. Dea 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. Dea 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 Naperville and Illinois
Billing and prescribing volume is not a quality rating.
Medicare Part B services
Close to the middle for clinicians listed under Internal Medicine in Naperville, IL (2024, 57 clinicians with data). Median for this group: 1,193. Middle half: 679 to 2,128.
More Medicare Part B services than 65% of clinicians listed under Internal Medicine in Illinois (2024, 3,231 clinicians with data). Median for this group: 696. Middle half: 284 to 1,352.
Medicare-allowed amount
A lower Medicare-allowed amount than 65% of clinicians listed under Internal Medicine in Naperville, IL (2024, 57 clinicians with data). Median for this group: $104,289. Middle half: $58,730 to $155,900.
Close to the middle for clinicians listed under Internal Medicine in Illinois (2024, 3,231 clinicians with data). Median for this group: $67,573. Middle half: $27,616 to $124,710.
Paid by Medicare
A lower Medicare payment amount than 65% of clinicians listed under Internal Medicine in Naperville, IL (2024, 57 clinicians with data). Median for this group: $81,855. Middle half: $43,990 to $125,626.
Close to the middle for clinicians listed under Internal Medicine in Illinois (2024, 3,231 clinicians with data). Median for this group: $52,732. Middle half: $21,099 to $98,198.
Medicare Part D prescriptions
Fewer Part D prescriptions than 95% of clinicians listed under Internal Medicine in Naperville, IL (2024, 58 clinicians with data). Median for this group: 3,209. Middle half: 927 to 5,468.
Fewer Part D prescriptions than 80% of clinicians listed under Internal Medicine in Illinois (2024, 3,708 clinicians with data). Median for this group: 1,080. Middle half: 101 to 4,782.
Part D drug cost
A lower Part D drug cost than 95% of clinicians listed under Internal Medicine in Naperville, IL (2024, 58 clinicians with data). Median for this group: $205,811. Middle half: $38,242 to $467,860.
A lower Part D drug cost than 80% of clinicians listed under Internal Medicine in Illinois (2024, 3,708 clinicians with data). Median for this group: $82,134. Middle half: $2,821 to $375,574.
74 active clinicians are listed under Internal Medicine with a practice address in Naperville, IL (7,195 in Illinois).
Addresses are self-reported to NPPES and may be out of date.
Telehealth indicator in Naperville
54.1% of these 74 clinicians have the CMS telehealth indicator.
71.6% of these 74 clinicians are listed by CMS as accepting Medicare assignment.
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 34% from 759 in 2017 to 1,019 in 2024.
- 2017: 759
- 2018: 273
- 2024: 1,019
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Medicare-allowed amount
Medicare-allowed amount decreased 10% from $77,071 in 2017 to $68,989 in 2024.
- 2017: $77,071
- 2018: $29,486
- 2024: $68,989
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Paid by Medicare
Paid by Medicare varied from year to year: $59,417 in 2017 and $57,105 in 2024.
- 2017: $59,417
- 2018: $19,209
- 2024: $57,105
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Medicare Part D prescriptions
Medicare Part D prescriptions decreased 97% from 2,064 in 2016 to 69 in 2024.
- 2016: 2,064
- 2017: 2,287
- 2018: 1,660
- 2019: 25
- 2024: 69
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30-day fills
30-day fills decreased 98% from 4,609 in 2016 to 85 in 2024.
- 2016: 4,609
- 2017: 5,229
- 2018: 3,566
- 2019: 37
- 2024: 85
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Part D drug cost
Part D drug cost decreased 99% from $72,066 in 2016 to $870 in 2024.
- 2016: $72,066
- 2017: $87,009
- 2018: $50,984
- 2019: $641
- 2024: $870
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Industry payments (Open Payments)
Industry payments (Open Payments) went from $460.15 in 2024 to $898.74 in 2025.
- 2024: $460.15
- 2025: $898.74
Sources: CMS Medicare Physician & Other Practitioners (2024), CMS Medicare Part D Prescribers (2024), CMS Open Payments (2025), CMS Doctors and Clinicians, CMS release of October 2, 2026, 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 2025 (payments made January 1 – December 31, 2025): 45 records totaling $898.74.
| Manufacturer | Payment Nature | Product | Type | Amount ($) |
|---|---|---|---|---|
| Bayer Healthcare Pharmaceuticals Inc. |
Food and Beverage
In-kind items and services
|
Kerendia | General | $32.81 |
| Eli Lilly and Company |
Food and Beverage
In-kind items and services
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MOUNJARO | General | $30.32 |
| Verity Pharmaceuticals Inc. |
Food and Beverage
Cash or cash equivalent
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Tlando | General | $28.65 |
| Verity Pharmaceuticals Inc. |
Food and Beverage
Cash or cash equivalent
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Tlando | General | $26.79 |
| Bayer Healthcare Pharmaceuticals Inc. |
Food and Beverage
In-kind items and services
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Kerendia | General | $26.63 |
| Verity Pharmaceuticals Inc. |
Food and Beverage
Cash or cash equivalent
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Tlando | General | $26.05 |
| Axsome Therapeutics, Inc. |
Food and Beverage
In-kind items and services
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Auvelity | General | $25.89 |
| AstraZeneca Pharmaceuticals LP |
Food and Beverage
In-kind items and services
|
— | General | $25.04 |
| Radius Health, Inc. |
Food and Beverage
In-kind items and services
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Tymlos | General | $24.55 |
| Xeris Pharmaceuticals, Inc. |
Food and Beverage
In-kind items and services
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RECORLEV | General | $23.85 |
| Corcept Therapeutics |
Food and Beverage
In-kind items and services
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Korlym | General | $23.69 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
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Ozempic | General | $21.39 |
| Otsuka America Pharmaceutical, Inc. |
Food and Beverage
In-kind items and services
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REXULTI | General | $21.31 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
|
— | General | $21.28 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
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Rybelsus | General | $21.23 |
| Phathom Pharmaceuticals, Inc. |
Food and Beverage
Cash or cash equivalent
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VOQUEZNA | General | $20.37 |
| Xeris Pharmaceuticals, Inc. |
Food and Beverage
In-kind items and services
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GVOKE HYPOPEN | General | $20.05 |
| Otsuka America Pharmaceutical, Inc. |
Food and Beverage
In-kind items and services
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REXULTI | General | $19.96 |
| Eli Lilly and Company |
Food and Beverage
In-kind items and services
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MOUNJARO | General | $19.92 |
| Eli Lilly and Company |
Food and Beverage
In-kind items and services
|
MOUNJARO | General | $19.69 |
| Bayer Healthcare Pharmaceuticals Inc. |
Food and Beverage
In-kind items and services
|
Kerendia | General | $19.31 |
| GlaxoSmithKline, LLC. |
Food and Beverage
In-kind items and services
|
TRELEGY ELLIPTA | General | $19.07 |
| ABBVIE INC. |
Food and Beverage
In-kind items and services
|
CREON | General | $18.88 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
|
Ozempic | General | $18.70 |
| GlaxoSmithKline, LLC. |
Food and Beverage
In-kind items and services
|
TRELEGY ELLIPTA | General | $18.26 |
(top 25 shown)
Source: CMS Open Payments, program year 2025, 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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198 | 127 | $244.47 | $130.71 |
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36415
Insertion of needle into vein for collection of blood sample
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167 | 146 | $24.76 | $8.65 |
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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
|
108 | 83 | $159.69 | $93.73 |
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99490
Chronic care management services, first 20 minutes of clinical staff time directed by health care professional, per calendar month
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99 | 37 | $112.20 | $64.35 |
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G0442
Annual alcohol misuse screening, 5 to 15 minutes
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85 | 85 | $48.05 | $19.41 |
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G0439
Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit
|
82 | 82 | $309.45 | $133.26 |
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G0444
Annual depression screening, 5 to 15 minutes
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79 | 79 | $48.05 | $19.41 |
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99497
Advance care planning, first 30 minutes
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68 | 68 | $226.20 | $83.86 |
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83036
Hemoglobin a1c level
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52 | 45 | $89.08 | $9.52 |
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G0136
Administration of a standardized, evidence-based social determinants of health risk assessment tool, 5-15 minutes
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37 | 37 | $48.70 | $19.53 |
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81003
Automated urinalysis test
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22 | 19 | $29.65 | $2.20 |
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99215
Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more
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22 | 20 | $343.74 | $185.96 |
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 |
|---|---|---|---|---|---|
| Tramadol Hcl | Tramadol Hcl | 17 | 327 | $71.87 | — |
| Hydrocodone-Acetaminophen | Hydrocodone/Acetaminophen | 15 | 361 | $461.50 | — |
| Diazepam | Diazepam | 13 | 390 | $98.52 | — |
| Lisinopril | Lisinopril | 12 | 828 | $192.59 | — |
| Alprazolam | Alprazolam | 12 | 275 | $45.87 | — |
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
NUCC 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
I20100608000085
IL
6002882503
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, CMS release of October 2, 2026
Health Service Systems, Inc
15505 E 127th St, Lemont, IL 604394433
Phone: 6302438888
Clinicians Sharing This Practice Address or Phone
Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.
Internal Medicine
Doctor of Medicine (M.D.)
Internal Medicine
Doctor of Medicine (M.D.)
Internal Medicine
Doctor of Medicine (M.D.)
Nurse Practitioner
Nurse Practitioner
Internal Medicine
Doctor of Medicine (M.D.)
Nurse Practitioner
APNCNP
Career & Practice History
NPI enumerated September 07, 2005.
No changes to the name, practice address, taxonomy or NPI status in this record have been observed in the monthly NPPES data files from January 2017 to November 2026.
NPI Administrative Meta
Other Internal Medicine Providers in Naperville
- Dr. Amish Doshi, MD
- Dr. Christine Amstadt, MD
- Dr. Barbara Emery-Stolzer, MD
- Dr. Ayesha Khan, MD
- Dr. Krishna Bathina, MD
- Dr. Hardeep Arora, MD
Mailing Address
1804 N Naper Blvd, Ste 103
Naperville, IL 605638830
Phone: 6306466200