Dr. John M. O'brien , MD
Internal Medicine โข Chicago, IL
1901 W Harrison St
Chicago, IL 606123714
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. John O'Brien is listed in NPPES under Internal Medicine.
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NPI assigned on June 30, 2006; this date does not establish years in practice.
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Published CMS data list 96 Original Medicare Part B services in 2023.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2023. Published rows only; this is not a quality measure.
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Published Part B service records, 2023:
- 99214 โ Established patient outpatient office visit: 80 service units.
- 99213 โ Established patient outpatient office visit: 16 service units.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2023. Units differ by code; these are not visits or a measure of quality.
CPTยฎ 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 ยท Guide: How to read Medicare Part B data
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Published CMS data list 187 Medicare Part D prescriptions, including refills, in 2024.
Source: CMS, Medicare Part D Prescribers โ 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 โ 42 prescription fills, including refills.
- Amlodipine Besylate โ 23 prescription fills, including refills.
- Famotidine โ 19 prescription fills, including refills.
Source: CMS, Medicare Part D Prescribers โ by Provider and Drug, 2024. Drug names come from pharmacy claims. Listing a drug here is not an endorsement or a recommendation.
See all 11 records in the table ยท Guide: How to read Medicare Part D prescriber data
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Fewer Part D prescriptions than 60% of clinicians listed under Internal Medicine in Chicago, IL (2024, 1,269 clinicians with data). Median for this group: 474. Middle half: 74 to 2,358.
Fewer Part D prescriptions than 65% 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.
Source: CMS, Medicare Part D Prescribers โ by Provider and Drug, 2024. Billing and prescribing volume is not a quality rating.
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Medicare Part B services went from 159 in 2019 to 96 in 2023.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2019โ2023.
Practice Location & Contact Primary Location
1901 W Harrison St
Chicago, IL 606123714
Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.
What Public CMS Data Show
Internal Medicine: NPPES taxonomy is a reported classification, not proof of board certification.
Medicare-allowed amount
About $9,757 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 โ by Provider and Service, 2023.
Paid by Medicare
About $7,055 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 โ by Provider and Service, 2023.
30-day fills
447 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
$2,377 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 โ by Provider and Drug, 2024.
Industry payments (Open Payments)
No Open Payments records are listed for this clinician for 2019โ2025.
NPI first issued
2006
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, โDoes your provider accept Medicare as full payment?โ
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.
Enrolled in Medicare (PECOS)
Dr. O'Brien 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. O'Brien 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 Chicago and Illinois
Billing and prescribing volume is not a quality rating.
Medicare Part D prescriptions
Fewer Part D prescriptions than 60% of clinicians listed under Internal Medicine in Chicago, IL (2024, 1,269 clinicians with data). Median for this group: 474. Middle half: 74 to 2,358.
Fewer Part D prescriptions than 65% 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.
Part D drug cost
A lower Part D drug cost than 70% of clinicians listed under Internal Medicine in Chicago, IL (2024, 1,269 clinicians with data). Median for this group: $40,678. Middle half: $1,543 to $232,098.
A lower Part D drug cost than 75% 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.
Medicare Part B
Comparisons use 2024 data. The latest CMS data for Dr. O'Brien are from 2023.
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.
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 decreased 40% from 159 in 2019 to 96 in 2023.
- 2019: 159
- 2020: 81
- 2021: 82
- 2022: 69
- 2023: 96
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Medicare-allowed amount
Medicare-allowed amount decreased 26% from $13,176 in 2019 to $9,757 in 2023.
- 2019: $13,176
- 2020: $6,643
- 2021: $9,679
- 2022: $7,431
- 2023: $9,757
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Paid by Medicare
Paid by Medicare decreased 24% from $9,302 in 2019 to $7,055 in 2023.
- 2019: $9,302
- 2020: $4,409
- 2021: $7,082
- 2022: $5,546
- 2023: $7,055
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Medicare Part D prescriptions
Medicare Part D prescriptions decreased 78% from 846 in 2020 to 187 in 2024.
- 2020: 846
- 2021: 763
- 2022: 786
- 2023: 697
- 2024: 187
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30-day fills
30-day fills decreased 79% from 2,123 in 2020 to 447 in 2024.
- 2020: 2,123
- 2021: 2,010
- 2022: 2,012
- 2023: 1,809
- 2024: 447
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Part D drug cost
Part D drug cost decreased 92% from $29,000 in 2020 to $2,377 in 2024.
- 2020: $29,000
- 2021: $16,650
- 2022: $27,794
- 2023: $34,739
- 2024: $2,377
Sources: CMS Medicare Physician & Other Practitioners (2023), CMS Medicare Part D Prescribers (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.
Performed Procedures & Service Volume
CPTยฎ is a registered trademark of the American Medical Association. CPT codes, descriptions and other data only are copyright 2016โ2022 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, 2017โ2023; 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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80 | 39 | $246.34 | $105.00 |
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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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16 | 15 | $168.00 | $84.84 |
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 2024.
| Brand Name | Generic Name | Prescriptions | Day Supply | Total Cost | Patients |
|---|---|---|---|---|---|
| Atorvastatin Calcium | Atorvastatin Calcium | 42 | 3,180 | $323.83 | 19 |
| Amlodipine Besylate | Amlodipine Besylate | 23 | 1,710 | $108.64 | โ |
| Famotidine | Famotidine | 19 | 1,710 | $99.76 | โ |
| Nifedipine Er | Nifedipine | 17 | 1,530 | $483.95 | โ |
| Albuterol Sulfate Hfa | Albuterol Sulfate | 17 | 467 | $750.21 | โ |
| Furosemide | Furosemide | 13 | 930 | $58.68 | โ |
| Metoprolol Succinate | Metoprolol Succinate | 12 | 720 | $30.89 | โ |
| Enalapril Maleate | Enalapril Maleate | 11 | 885 | $284.97 | โ |
| Metformin Hcl | Metformin Hcl | 11 | 990 | $44.83 | โ |
| Tamsulosin Hcl | Tamsulosin Hcl | 11 | 750 | $82.45 | โ |
| Hydralazine Hcl | Hydralazine Hcl | 11 | 450 | $108.61 | โ |
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: 2021-04-28NUCC 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 PECOSPRACTITIONER - INTERNAL MEDICINE
I20101221000413
IL
9537357330
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.
Internal Medicine - Gastroenterology
Doctor of Medicine (M.D.)
Physician Assistant
Physician Assistant
Internal Medicine - Hematology & Oncology
Doctor of Medicine (M.D.)
Emergency Medicine
Internal Medicine - Cardiovascular Disease
Doctor of Medicine (M.D.), Master of Public Health
Psychiatry & Neurology - Neurology
Doctor of Medicine (M.D.)
Career & Practice History Timeline
Changes recorded in monthly NPPES data files: addresses, names, credentials, specialties and NPI status
Internal Medicine (license number reported to NPPES: IL 036082069)
NPI status registered as active in NPPES database
Registered at 1901 W HARRISON ST, CHICAGO, IL 606123714 (Tel: 3128646000)
Registered at 1901 W HARRISON ST, CHICAGO, IL 606123714 (Tel: 3128646000)
Recorded as JOHN O'BRIEN, MD
Internal Medicine
First registered as active Individual Practitioner in NPPES Database.
NPI Administrative Meta
Other Internal Medicine Providers in Chicago
- Dr. Matthew Levine, MD
- Dr. Chinyere Ikwu, MD
- Dr. Muriel Battaglia, MD
- Dr. Sowmya Mikkilineni, MD
- Dr. Alok Swaroop, MD, PhD
- Dr. Eric Perkey, MD
Mailing Address
1901 W Harrison St
Chicago, IL 606123714
Phone: 3128646000