Dr. Esther Kwak , DO
Internal Medicine • Evanston, IL
2650 Ridge Ave., Office Of The Chief Resident
Evanston, IL 60201
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 March 27, 2019; this date does not establish years in practice.
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Published CMS data list 118 Original Medicare Part B services in 2023.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2023. Published rows only; this is not a quality measure.
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Published Part B service records, 2023:
- 99233 — Subsequent hospital care with moderate levelof medical decision making: 58 service units.
- 99232 — Subsequent hospital care with moderate levelof medical decision making: 36 service units.
- 99239 — Hospital discharge day management: 24 service units.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2023. Units differ by code; these are not visits or a measure of quality.
CPT® only copyright 2022 American Medical Association. All rights reserved. Service names are shortened from CPT Consumer Friendly Descriptors (CMS data, 2023). CPT notice
See the full table · Guide: How to read Medicare Part B data
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Published CMS data list 28 Medicare Part D prescriptions, including refills, in 2022.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2022. Published rows only; this is not a quality measure.
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Published Part D records, 2022:
- Atorvastatin Calcium — 17 prescription fills, including refills.
- Amlodipine Besylate — 11 prescription fills, including refills.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2022. Drug names come from pharmacy claims. Listing a drug here is not an endorsement or a recommendation.
See the full table · Guide: How to read Medicare Part D prescriber data
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Medicare Part B services went from 129 in 2022 to 118 in 2023.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2022–2023.
Practice Location & Contact Primary Location
2650 Ridge Ave.
Office Of The Chief Resident
Evanston, IL 60201
NPPES lists 1 additional practice-address record in Evanston, IL. See the list
Source: CMS NPPES NPI Registry, practice location records; release date unavailable.
Listings do not confirm current availability, employment or a shared ownership network.
What Public CMS Data Show
Internal Medicine: NPPES taxonomy is a reported classification, not proof of board certification.
Medicare-allowed amount
About $12,703 in 2023
The total amount Medicare approved for these services in 2023. 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, 2023.
Paid by Medicare
About $9,374 in 2023
The part of the Medicare-allowed amount that Medicare itself paid in 2023, 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, 2023.
30-day fills
58 standardized 30-day fills in 2022
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
$492 in 2022
The total cost of these prescriptions in 2022, 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, 2022.
Open Payments general payments, program year 2025
All general payments: $355.64 across 6 records.
By nature of payment
- Food and Beverage: $355.64 across 6 records.
Reporting-company totals (3 largest of 6)
- Medtronic, Inc.: $133.35 across 1 record.
- BIOTRONIK INC.: $82.71 across 1 record.
- Sanofi and Genzyme US Companies: $50.44 across 1 record.
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).
NPI first issued
2019
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.
Medicare assignment not listed
CMS data do not show whether this clinician accepts Medicare assignment. This does not mean they do not accept Medicare. Ask the office.
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?”
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.
Can order Medicare-covered services
CMS lists Dr. Kwak as eligible to order or refer durable medical equipment (DME) 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 Evanston and Illinois
Billing and prescribing volume is not a quality rating.
Medicare Part B
Comparisons use 2024 data. The latest CMS data for Dr. Kwak are from 2023.
Medicare Part D
Comparisons use 2024 data. The latest CMS data for Dr. Kwak are from 2022.
178 active clinicians are listed under Internal Medicine with a practice address in Evanston, IL (7,245 in Illinois).
Addresses are self-reported to NPPES and may be out of date.
Telehealth indicator in Evanston
14.6% of these 178 clinicians have the CMS telehealth indicator.
34.3% of these 178 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 stayed about the same: 129 in 2022 and 118 in 2023.
- 2022: 129
- 2023: 118
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Medicare-allowed amount
Medicare-allowed amount stayed about the same: $11,834 in 2022 and $12,703 in 2023.
- 2022: $11,834
- 2023: $12,703
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Paid by Medicare
Paid by Medicare stayed about the same: $9,290 in 2022 and $9,374 in 2023.
- 2022: $9,290
- 2023: $9,374
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Medicare Part D prescriptions
Medicare Part D prescriptions went from 14 in 2020 to 28 in 2022.
- 2020: 14
- 2021: 49
- 2022: 28
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30-day fills
30-day fills increased 81% from 32 in 2020 to 58 in 2022.
- 2020: 32
- 2021: 114
- 2022: 58
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Part D drug cost
Part D drug cost went from $329 in 2020 to $492 in 2022.
- 2020: $329
- 2021: $729
- 2022: $492
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Industry payments (Open Payments)
Industry payments (Open Payments) went from $32.45 in 2020 to $355.64 in 2025.
- 2020: $32.45
- 2024: $566.03
- 2025: $355.64
Sources: CMS Medicare Physician & Other Practitioners (2023), CMS Medicare Part D Prescribers (2022), CMS Open Payments (2025), 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 2025 (payments made January 1 – December 31, 2025): fewer than 11 records totaling $355.64.
| Manufacturer | Payment Nature | Product | Type | Amount ($) |
|---|---|---|---|---|
| Medtronic, Inc. |
Food and Beverage
In-kind items and services
|
— | General | $133.35 |
| BIOTRONIK INC. |
Food and Beverage
In-kind items and services
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— | General | $82.71 |
| Sanofi and Genzyme US Companies |
Food and Beverage
In-kind items and services
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— | General | $50.44 |
| ABIOMED |
Food and Beverage
In-kind items and services
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— | General | $43.06 |
| Boehringer Ingelheim Pharmaceuticals, Inc. |
Food and Beverage
In-kind items and services
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JARDIANCE | General | $23.93 |
| CVRx, Inc. |
Food and Beverage
Cash or cash equivalent
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Barostim Neo System | General | $22.15 |
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 2021–2022 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, 2022–2023; 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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99233
Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes
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58 | 27 | $229.00 | $119.36 |
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99232
Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes
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36 | 18 | $160.00 | $83.19 |
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99239
Hospital discharge day management, more than 30 minutes
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24 | 24 | $235.00 | $116.04 |
Source: CMS Part B by Provider and Service, 2023; 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 2022.
| Brand Name | Generic Name | Prescriptions | Day Supply | Total Cost | Patients |
|---|---|---|---|---|---|
| Atorvastatin Calcium | Atorvastatin Calcium | 17 | 1,050 | $268.21 | — |
| Amlodipine Besylate | Amlodipine Besylate | 11 | 690 | $223.46 | — |
Source: CMS Part D by Provider and Drug, 2022; rows below 11 claims omitted by CMS; volume isn’t quality. Privacy limits
Specialties & License Numbers Reported to NPPES
Self-certified to NPPES: 2022-05-09NUCC 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.
NUCC Taxonomy Code: 390200000X
An individual who is enrolled in an organized health care education/training program leading to a degree, certification, registration, and/or licensure to provide health care.
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.
Medicare (PECOS) Enrollment & Ordering Eligibility
Source: CMS PECOSSources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.
Secondary Practice Locations
2650 Ridge Ave Ste 1304
Evanston, IL 602011700
Phone: 8475702700
Clinicians Sharing This Practice Address or Phone
Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.
Student in an Organized Health Care Education/Training Program
Internal Medicine
Doctor of Medicine (M.D.)
Internal Medicine
Doctor of Medicine (M.D.)
Career & Practice History Timeline
Changes recorded in monthly NPPES data files: addresses, names, credentials, specialties and NPI status
Registered at 2650 RIDGE AVE., OFFICE OF THE CHIEF RESIDENT, EVANSTON, IL 60201 (Tel: 8475702505)
Registered at 2650 RIDGE AVE., OFFICE OF THE CHIEF RESIDENT, EVANSTON, IL 60201 (Tel: 8475702505)
Recorded as ESTHER KWAK, DO
NPI status registered as active in NPPES database
Registered at 2650 RIDGE AVE STE 1304, EVANSTON, IL 602011700 (Tel: 8475702700)
Registered at 180 HARVESTER DR STE 110, BURR RIDGE, IL 605276686 (Tel: 7737021150)
Recorded as ESTHER KWAK
Student in an Organized Health Care Education/Training Program
First registered as active Individual Practitioner in NPPES Database.
NPI Administrative Meta
Other Internal Medicine Providers in Evanston
- Dr. Pitud Rangsithienchai, MD
- Dr. John Fultz, MD
- Dr. Angela Bicos, MD
- Dr. Robert Chris, MD
- Dr. Tammy Yao-Hong, DO
- Dr. Ki Seok Won, MD
Mailing Address
2650 Ridge Ave., Office Of The Chief Resident
Evanston, IL 60201
Phone: 8475702505