Dr. Gregory James Clark, MD
- Medicare services, 2019
- 1,277
- Part D claims, 2021
- 15
- Hospital affiliations
- 1
- Industry payments
- $140
- State license
- 1
- Practice address
- 600 N College Avenue, Geneseo, IL 61254
- Practice phone
- Call (309) 944-6431
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. Clark's professional email, personal email and mobile number
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Dr. Gregory James Clark is an internist in Geneseo, Illinois
Dr. Clark practices at Hammond-Henry Hospital in Geneseo, Illinois, part of HammondHenry Hospital.
Dr. Clark's NPI, 1386730836, was assigned on October 4, 2006. Dr. Clark holds Iowa license MD-43163.
- NPI
- 1386730836NPI Registry (opens in a new tab)
- NPI enumeration date
- October 4, 2006
- NPI status
- Active
- Practice phone
- (309) 944-6431
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Affiliation Data
Dr. Gregory James Clark practices at Hammond-Henry Hospital in Geneseo, Illinois
Dr. Clark's primary practice is Hammond-Henry Hospital, at 600 N College Avenue, Geneseo, IL 61254 in Henry County. The practice phone is (309) 944-6431.
- Hammond-Henry Hospital600 N College Avenue, Geneseo, IL 61254 · Henry CountyPhone(309) 944-6431
Source: Dmand AI Affiliation Data
Dr. Gregory James Clark is affiliated with 1 site of care
Dr. Clark's primary practice is Hammond-Henry Hospital in Geneseo, Illinois, part of HammondHenry Hospital.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Gregory James Clark's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Clark practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Hammond-Henry Hospital | Available with a free account |
Source: Dmand AI Technology Install Data
For health IT teams
Dmand AI maps EHR vendors, IT decision makers and buying committees across HammondHenry Hospital and 6.2K+ hospitals, with verified contacts in the same login.
Dr. Gregory James Clark is one of 5,652 internists in Illinois
Internal medicine is Dr. Clark's primary specialty in the NPI Registry, under taxonomy code 207R00000X. Dr. Clark is licensed in Iowa.
Specialties and state licenses
- Internal medicine, IowaPrimary
Internists near Dr. Clark
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. Gregory James Clark billed Medicare for 1,277 services in 2019
CMS data shows 1,277 Medicare services from Dr. Clark across 18 procedure codes in 2019. Medicare paid $27,211 for them. Every service was in an office.
Dr. Clark's Medicare services by type, 2018 to 2019
- 2018
- 2019
- Lab and pathology
- 2018: 9192019: 61433%
- Office and hospital visits
- 2018: 5992019: 36639%
- Surgery
- 2018: 2742019: 21721%
- Tests and treatments
- 2018: 1512019: 6259%
- Imaging
- 2018: 292019: 1838%
- Other services
- 2018: 872019: 0100%
Dr. Clark compared with the Illinois median for internists, 2019
- Dr. Clark
- Illinois median
- Medicare services
- 1,277vs 5662.3 times
- Part D claims
- 15vs 28495% below
Medians across 5,192 internists in Illinois with Dmand AI profiles that report each measure.
Dr. Clark's most billed Medicare procedure codes, 2019
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
Need commercial claims for Dr. Clark?
Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Clark and other internists in Illinois.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Gregory James Clark's patients have a median age of 69
Across all payers, Dmand AI patient panel data puts Dr. Clark's median patient age at 69, with 49% women.
Dr. Clark's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 69
Patient panel by sex, all payers
- Women49%
- Men50%
Source: Dmand AI Patient Panel Data
Dr. Gregory James Clark wrote 15 Medicare Part D claims in 2021
In 2021, Dr. Clark wrote 15 Medicare Part D claims. They cover 1 drug, with $1,260 in total drug cost. In 2020, CMS named 47 claims across 3 drugs.
Dr. Clark's most prescribed drugs by claims, 2021
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, 2020 to 2021
- 2020
- 2021
- Claims for drugs CMS names
- 2020: 472021: 1568%
Drugs named by CMS: 1 in 2021, 3 in 2020.
Source: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026
For MedTech and pharma teams
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Dr. Gregory James Clark received $140 in industry payments from 2016 to 2023
CMS Open Payments shows 8 general payments to Dr. Clark from 5 drug and device companies from 2016 to 2023. Food and beverage make up the largest share, 100% of the total. Abbott Laboratories paid the most, $49.
General payments to Dr. Clark by program year, 2016 to 2023
Companies that paid Dr. Clark the most, 2016 to 2023
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Sources for Dr. Gregory James Clark'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 | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy Data |
| 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) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| 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. Gregory James Clark
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. Gregory James Clark's NPI number?
Dr. Gregory James Clark's NPI number is 1386730836. It was assigned on October 4, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Gregory James Clark?
Dr. Gregory James Clark is an internist in Geneseo, Illinois. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. Gregory James Clark practice?
Dr. Clark practices at 600 N College Avenue, Geneseo, IL 61254. Dr. Clark's primary practice is Hammond-Henry Hospital in Geneseo, Illinois, part of HammondHenry Hospital.
What is Dr. Gregory James Clark's office phone number?
The practice phone on file for Dr. Clark is (309) 944-6431.
What is Dr. Gregory James Clark's medical license number?
Dr. Clark holds Iowa license MD-43163.
Which hospitals is Dr. Gregory James Clark affiliated with?
Dr. Clark practices at Hammond-Henry Hospital in Geneseo, Illinois.
Does Dr. Gregory James Clark accept Medicare?
Yes. CMS data shows Dr. Clark billed Medicare for 1,277 services in 2019.
What services does Dr. Gregory James Clark bill to Medicare?
In 2019, Dr. Clark's most billed Medicare services were surgery: heart and blood vessels (36415), office visit, established patient (99214) and office visit, established patient (99213).
What drugs does Dr. Gregory James Clark prescribe most?
In 2021 Medicare Part D data, Dr. Clark's most prescribed drugs by claims were Novofine Autocover.
Has Dr. Gregory James Clark received payments from drug or device companies?
CMS Open Payments shows $140 in general payments to Dr. Clark from 5 companies from 2016 to 2023. The largest total came from Abbott Laboratories.
How long has Dr. Gregory James Clark been practicing?
Dr. Clark's NPI was assigned in 2006.
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