Independent US Healthcare Provider Directory & Public Medical Database Patient Guides

James Ahn

Internal Medicine โ€ข Chicago, IL

Active NPI 1457594574 Individual Practitioner Male Practitioner
Practice location in NPPES

5841 S Maryland Ave
Chicago, IL 606371443

Call 8888240200 Location details and other listings
Medical Disclaimer

This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.

Practice Location & Contact Primary Location

Practice Address

5841 S Maryland Ave

Chicago, IL 606371443

Telephone 8888240200
Organization at the Same NPPES Address or Phone
University Of Chicago Facility NPI 1821048786

Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.

Medicare patients

113 people with Original Medicare in 2024

Different Original Medicare patients in 2024; counts below 11 are hidden; this does not show availability or quality.

Source: CMS, Medicare Physician & Other Practitioners โ€“ by Provider, 2024.

Medicare-allowed amount

About $20,200 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.

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 โ€“ by Provider and Service, 2024.

Paid by Medicare

About $16,026 in 2024

The part of the Medicare-allowed amount that Medicare itself paid in 2024, after patients' deductibles and coinsurance.

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 โ€“ by Provider and Service, 2024.

Industry payments (Open Payments)

Fewer than 11 payment records totaling $26.25 in 2024

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.

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 2024.

Guide: How to read an Open Payments record

NPI first issued

2009

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, โ€œDoes your provider accept Medicare as full payment?โ€

Guide: What Medicare assignment means

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.

Guide: How Medicare covers telehealth

Enrolled in Medicare (PECOS)

James Ahn 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.

Guide: What Medicare enrollment (PECOS) means

Can order Medicare-covered services

CMS lists James Ahn 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.

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.

Guide: What ordering and referring status means

Compared with the same specialty in Chicago and Illinois

Billing and prescribing volume is not a quality rating.

Medicare Part B services

Fewer Medicare Part B services than 80% of clinicians listed under Internal Medicine in Chicago, IL (2024, 1,008 clinicians with data). Median for this group: 406. Middle half: 157 to 820.

Fewer Medicare Part B services than 85% 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.

Medicare-allowed amount

A lower Medicare-allowed amount than 65% of clinicians listed under Internal Medicine in Chicago, IL (2024, 1,008 clinicians with data). Median for this group: $41,573. Middle half: $14,662 to $79,189.

A lower Medicare-allowed amount than 80% 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.

Paid by Medicare

A lower Medicare payment amount than 65% of clinicians listed under Internal Medicine in Chicago, IL (2024, 1,008 clinicians with data). Median for this group: $31,519. Middle half: $10,954 to $62,185.

A lower Medicare payment amount than 75% 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.

2,870 active clinicians are listed under Internal Medicine with a practice address in Chicago, IL (7,245 in Illinois).

Addresses are self-reported to NPPES and may be out of date.

Telehealth indicator in Chicago

13.3% of these 2,870 clinicians have the CMS telehealth indicator.

38.5% of these 2,870 clinicians are listed by CMS as accepting Medicare assignment.

Sources: CMS Medicare Physician & Other Practitioners (2024), CMS Open Payments (2024), CMS Doctors and Clinicians, CMS NPPES NPI Registry. Specialty names follow the NUCC Health Care Provider Taxonomy.

Text: T-MedInfo ยท 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

Open Payments ยท Program Year 2024

Program year 2024 (payments made January 1 โ€“ December 31, 2024): fewer than 11 records totaling $26.25.

Manufacturer Payment Nature Product Type Amount ($)
Mindray DS USA, Inc.
Food and Beverage
In-kind items and services
TE7 MAX General $26.25

Source: CMS Open Payments, program year 2024, released June 30, 2026.

Performed Procedures & Service Volume

Services billed to Original Medicare Part B in 2024.

CMS Part B ยท Data Year 2024
Reporting Year:

CPTยฎ is a registered trademark of the American Medical Association. CPT codes, descriptions and other data only are copyright 2016โ€“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 โ€“ by Provider and Service data, 2017โ€“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
99285 Emergency department visit with high level of medical decision making
92 89 $739.87 $197.44
99284 Emergency department visit with moderate level of medical decision making
15 15 $499.00 $135.72

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.

Specialties & License Numbers Reported to NPPES

Internal Medicine Primary Specialty

NUCC Taxonomy Code: 207R00000X

License # reported to NPPES IL 036125480

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.

Check License Status with the State Board License numbers are self-reported to NPPES; T-MedInfo does not confirm them against state records. Current status: Illinois Department of Financial and Professional Regulation.
Look Up on State Board Site

Medicare (PECOS) Enrollment & Ordering Eligibility

Source: CMS PECOS
Medicare FFS Enrollment Status Medicare Enrollment on File
CMS Provider Specialty

PRACTITIONER - EMERGENCY MEDICINE

Medicare Enrollment ID

I20101201000722

Enrollment State Jurisdiction

IL

PECOS Control ID

5890981963

Medicare Order & Referring Eligibility
Clinical Lab & Imaging (Part B) Eligible
Durable Medical Equipment (DME) Eligible
Home Health Agency (HHA) Eligible
Power Mobility Devices (PMD) Eligible

Sources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.

Clinicians Sharing This Practice Address or Phone

Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.

37 listed
Calvin Adatsi

Nurse Practitioner - Family

NPI 1033767082
Ayman Al-Hendy

Obstetrics & Gynecology

NPI 1023184637
Stephen Bennett

Family Medicine

NPI 1013978766
Paul Chang

Radiology - Diagnostic Radiology

NPI 1023080983
Michael Davidson

Internal Medicine - Cardiovascular Disease

NPI 1023033321
Alexandra Dumitrescu

Internal Medicine

NPI 1003078049

Career & Practice History Timeline

Changes recorded in monthly NPPES data files: addresses, names, credentials, specialties and NPI status

10 Historical Events
๐Ÿ“
Updated Practice Location April 18, 2022

Registered at 5841 S MARYLAND AVE, CHICAGO, IL 606371443 (Tel: 8888240200)

๐Ÿ“
Updated Business Mailing Address April 18, 2022

Registered at 150 HARVESTER DR, SUITE 300, BURR RIDGE, IL 605275919

๐Ÿ‘ค
Provider Name / Credentials Updated April 18, 2022

Recorded as JAMES AHN

๐ŸŽ“
Medical Taxonomy / Specialty Registered (Primary Specialty) April 18, 2022

Internal Medicine (license number reported to NPPES: IL 036125480)

โœ…
NPI Profile Active April 20, 2009

NPI status registered as active in NPPES database

๐Ÿ“
Practice Location (Initial Record) April 20, 2009

Registered at 1529 S STATE ST APT 18-B, CHICAGO, IL 606053107 (Tel: 3127535396)

๐Ÿ“
Business Mailing Address (Initial Record) April 20, 2009

Registered at 1529 S STATE ST APT 18-B, CHICAGO, IL 606053107

๐Ÿ‘ค
Provider Name / Credentials (Initial Record) April 20, 2009

Recorded as JAMES AHN, M.D.

๐ŸŽ“
Medical Taxonomy / Specialty Registered (Primary Specialty) April 20, 2009

Emergency Medicine (license number reported to NPPES: IL 125052540)

๐ŸŸข
Initial NPI Registration & Enumeration April 20, 2009

First registered as active Individual Practitioner in NPPES Database.

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NPI Administrative Meta

NPI Number: 1457594574
Entity Type:
Individual Provider Physician, Nurse Practitioner, or Solo Healthcare Professional (Type 1 NPI)
Enumeration Date: April 20, 2009
Last Update: October 24, 2022
Sole Proprietor: No

Other Internal Medicine Providers in Chicago

All Internal Medicine Providers in Chicago

Mailing Address

150 Harvester Dr, Suite 300

Burr Ridge, IL 605275919

About This Data NPPES fields (address, phone, specialty, license) are self-reported and may be outdated; Medicare fields follow the CMS dataset named in each section. Correct directly at NPPES.