Dr. Geoffrey R. Sebastian, MD
- Medicare services, 2023
- 481
- Part D claims, 2024
- 209
- Industry payments
- $44
- Affiliated sites
- 2
- Medical groups
- 2
- Practice address
- 2 E 22nd St Suite 215 Suite 215, Lombard, IL 60148-6125
- Practice phone
- Call (630) 376-6317
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Prospect Healthcare
Primary care practice · Lombard, Illinois
Find Dr. Sebastian's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. Geoffrey R. Sebastian is an internist in Chicago, Illinois
Dr. Sebastian practices at Prospect Healthcare in Lombard, Illinois.
Dr. Sebastian's NPI, 1114991163, was assigned on February 15, 2006. Dr. Sebastian graduated from Rush Medical College of Rush University in 1991. Dr. Sebastian holds Illinois license 036087696.
- NPI
- 1114991163NPI Registry (opens in a new tab)
- NPI enumeration date
- February 15, 2006
- NPI status
- Active
- Practice phone
- (630) 376-6317
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 61
- Medical school graduation
- 1991
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Geoffrey R. Sebastian practices in Lombard and Chicago
Dr. Sebastian's primary practice is Prospect Healthcare, at 2 E 22nd St Suite 215 Suite 215, Lombard, IL 60148-6125. The practice phone is (630) 376-6317. The NPI Registry lists Dr. Sebastian's practice address as 251 E Huron St, Chicago, IL 60611.
- Prospect HealthcarePrimary2 E 22nd St Suite 215 Suite 215, Lombard, IL 60148-6125Phone(630) 376-6317
- NPI Registry address251 E Huron St, Chicago, IL 60611 · Cook CountyPhone(847) 839-1111
Sources: NPPES NPI Registry (CMS); Dmand AI Affiliation Data; Doctors and Clinicians National Downloadable File (CMS); and Dmand AI Practice Data
Dr. Geoffrey R. Sebastian is affiliated with 2 sites of care and 2 medical groups
Dr. Sebastian's primary practice is Prospect Healthcare in Lombard, Illinois. The medical group on file is Prospect Health Care. Dmand AI also links Dr. Sebastian to 1 more group practice or clinic and 1 medical group, each named with a free account.
Sources: Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dmand AI tracks the EHR system at Dr. Geoffrey R. Sebastian's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Sebastian practices, 2 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Prospect Healthcare | Available with a free account |
| +1 more site and 1 medical group | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Geoffrey R. Sebastian is one of 5,652 internists in Illinois
Internal medicine is Dr. Sebastian's primary specialty in the NPI Registry, under taxonomy code 207R00000X. Dr. Sebastian is licensed in Illinois.
Specialties and state licenses
- Internal medicine, IllinoisPrimary
Internists near Dr. Sebastian
Counts of internists with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. Geoffrey R. Sebastian billed Medicare for 481 services in 2023
CMS data shows 481 Medicare services from Dr. Sebastian across 5 procedure codes in 2023. Medicare paid $34,649 for them. Every service was in an office.
Dr. Sebastian's Medicare services by type, 2022 to 2023
- 2022
- 2023
- Office and hospital visits
- 2022: 8452023: 31862%
- Other services
- 2022: 4912023: 16367%
- Lab and pathology
- 2022: 742023: 0100%
- Tests and treatments
- 2022: 172023: 0100%
Dr. Sebastian compared with the Illinois median for internists, 2023
- Dr. Sebastian
- Illinois median
- Medicare services
- 481vs 56615% below
- Part D claims
- 46vs 28484% below
Medians across 5,192 internists in Illinois with Dmand AI profiles that report each measure.
Dr. Sebastian's most billed Medicare procedure codes, 2023
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
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Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Sebastian and other internists in Illinois.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Geoffrey R. Sebastian's patients have a median age of 78
Across all payers, Dmand AI patient panel data puts Dr. Sebastian's median patient age at 78, with 82% women.
Dr. Sebastian's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 78
Patient panel by sex, all payers
- Women82%
- Men14%
Source: Dmand AI Patient Panel Data
Dr. Geoffrey R. Sebastian wrote 209 Medicare Part D claims in 2024
In 2024, Dr. Sebastian wrote 209 Medicare Part D claims for 38 patients. 80% of them were for generic drugs. CMS names the drug for 46 of them, across 3 drugs with 11 or more claims each, at $1,070 in total drug cost. In 2023, CMS named 1,854 claims across 61 drugs.
Dr. Sebastian's Part D claims by kind of drug, 2024
- Generic168 claims80%
- Brand-name and other41 claims20%
Dr. Sebastian's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Part D claims for drugs CMS names, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 1,8542024: 4698%
Drugs named by CMS: 3 in 2024, 61 in 2023.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
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Dr. Geoffrey R. Sebastian received $44 in industry payments from 2019 to 2021
CMS Open Payments shows 2 general payments to Dr. Sebastian from 1 drug or device company from 2019 to 2021. Food and beverage make up the largest share, 100% of the total. Astellas Pharma US Inc paid the most, $44.
General payments to Dr. Sebastian by program year, 2019 to 2021
Companies that paid Dr. Sebastian the most, 2019 to 2021
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Geoffrey R. Sebastian graduated from Rush Medical College of Rush University
Dr. Sebastian graduated from Rush Medical College of Rush University in 1991.
- Medical school
Source: Dmand AI Professional Profile Data
Sources for Dr. Geoffrey R. Sebastian's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Affiliation DataDoctors and Clinicians National Downloadable File (CMS) (opens in a new tab)Dmand AI Practice Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDoctors and Clinicians National Downloadable File (CMS) (opens in a new tab) |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel Data |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. Geoffrey R. Sebastian
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. Geoffrey R. Sebastian's NPI number?
Dr. Geoffrey R. Sebastian's NPI number is 1114991163. It was assigned on February 15, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Geoffrey R. Sebastian?
Dr. Geoffrey R. Sebastian is an internist in Chicago, Illinois. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. Geoffrey R. Sebastian practice?
Dr. Sebastian practices at 2 E 22nd St Suite 215 Suite 215, Lombard, IL 60148-6125. Dr. Sebastian also practices at 251 E Huron St, Chicago, IL 60611. Dr. Sebastian's primary practice is Prospect Healthcare in Lombard, Illinois. Dmand AI also links Dr. Sebastian to 1 group practice or clinic and 1 medical group.
What is Dr. Geoffrey R. Sebastian's office phone number?
The practice phone on file for Dr. Sebastian is (630) 376-6317.
What is Dr. Geoffrey R. Sebastian's medical license number?
Dr. Sebastian holds Illinois license 036087696.
What medical group is Dr. Geoffrey R. Sebastian part of?
Dr. Sebastian is linked to Prospect Health Care. Dmand AI links Dr. Sebastian to 1 more medical group.
Does Dr. Geoffrey R. Sebastian accept Medicare?
Yes. CMS data shows Dr. Sebastian billed Medicare for 481 services in 2023.
What services does Dr. Geoffrey R. Sebastian bill to Medicare?
In 2023, Dr. Sebastian's most billed Medicare services were home visit (99349), medicare service (G0179) and home visit (99348).
Where did Dr. Geoffrey R. Sebastian go to medical school?
Dr. Sebastian graduated from Rush Medical College of Rush University in 1991.
What drugs does Dr. Geoffrey R. Sebastian prescribe most?
In 2024 Medicare Part D data, Dr. Sebastian's most prescribed drugs by claims were Allopurinol, Metoprolol Succinate and Albuterol Sulfate Hfa.
Has Dr. Geoffrey R. Sebastian received payments from drug or device companies?
CMS Open Payments shows $44 in general payments to Dr. Sebastian from 1 company from 2019 to 2021. The largest total came from Astellas Pharma US Inc.
How long has Dr. Geoffrey R. Sebastian been practicing?
Dr. Sebastian graduated from medical school in 1991, 35 years ago.
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