NPPES file of Aug 9, 2026

James Ralph Clark, M.D.

Gastroenterology Physician · Downers Grove, IL

James Ralph Clark, M.D. is a gastroenterology physician with a practice address in Downers Grove, Illinois, and NPI 1588640650, issued on Dec 20, 2005. Check the license on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.

Record from CMS NPPES, file of Aug 9, 2026 · Medicare files 2024 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1588640650
Name
James Ralph Clark
Credential
M.D.
Primary taxonomy
Gastroenterology Physician 207RG0100X
Practice location
3825 Highland Ave, Downers Grove, IL 60515
Phone
(630) 434-9312
Enumerated
Dec 20, 2005
Record last updated
Jul 8, 2007 (not updated in 19 years: call before relying on the address or phone)
Fax
(630) 434-9360
Medicare enrollment
Enrolled (PECOS I20040409000124); accepts Medicare assignment
Medical or professional school
University Of Illinois College Of Med (Chi/Peor/Rock/Chm-Urb), 1990
Telehealth
Offers telehealth (CMS)
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). Enrollment, assignment, school and telehealth: CMS Doctors and Clinicians file, Aug 2026. A record is not a license: verify it with the state board.
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8 nearest gastroenterology physician records → All 887 in Illinois → Look up another NPI →

Also registered at 3825 Highland Ave

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Mani Akkineni, M.D.Specialist1467456186
  2. Medha Amin, MDObstetrics Physician1912197534
  3. Teresita Avila, M.D.Specialist1386649317
  4. Lara Bakhos, M.D.Cardiovascular Disease Physician1730336652
  5. Jennifer Balash, M.D.Obstetrics & Gynecology Physician1487881025
  6. Shamita Bansore, MDObstetrics & Gynecology Physician1700813771

Verify James Ralph Clark in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersIllinois Department of Financial and Professional RegulationCheck the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Open the Illinois license search

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10% more Medicare Part D claims than the average gastroenterology physician in 2024

889 Medicare Part D claims for 376 beneficiaries, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D. Brand-name drugs were 22% of claims.

  1. James Clark889
  2. Specialty average811

Most prescribed

  1. Pantoprazole Sodium299 claims
  2. Omeprazole100 claims
  3. Gavilyte-G75 claims
  4. Mesalamine60 claims
  5. Peg-3350 And Electrolytes44 claims
  6. Plenvu42 claims

Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.

Industry payments in 2024: $1,316.39

65 payments; by number, the most common kind was food and beverage; the largest payer was Janssen Biotech, Inc. The 13,350 providers of this specialty with any payment received $5,015.95 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.

  1. James Clark$1,316.39
  2. Specialty average$5,015.95

Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.

Bills Medicare through one group practice

  1. GI Partners OF Illinois LLCLibertyville, IL

Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).

James Ralph Clark among 887 gastroenterology physician records in Illinois

James Ralph Clark, M.D. is one of 887 gastroenterology physician records with a practice address in Illinois. 85% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2005, is newer than 0% of them.

  • NPI issued2005 · 0% of these records are older, 85% newer
  • In a Medicare fileYes · 85% of these records are
  • In the CMS Doctors and Clinicians fileYes · 72% of these records are
  • Graduated1990 · median 2003 among the 643 with a school on file
  • Record last updated2007 · 49% of these records were not updated in five years or more

Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RG0100X and a Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).

Gastroenterology Physician providers in Illinois

There are 887 gastroenterology physician records in Illinois.

All 887 in Illinois → Every provider in Downers Grove → Gastroenterology Physician nationwide →

The 8 gastroenterology physician records with the nearest ZIP codes

  1. Anshuman Chawla, M.D.Downers Grove, IL 605151841276417
  2. David Gerard, M.D.Downers Grove, IL 605151942312210
  3. John Holden, MDDowners Grove, IL 605151356341846
  4. Manfred Raiser, M.D.Downers Grove, IL 605151306958665
  5. Rockford Yapp, M.D., M.P.H.Downers Grove, IL 605151356327910
  6. Laura Hamad, DOWoodridge, IL 605171699186890
  7. Carl CalandraHinsdale, IL 605211366527418
  8. Suman Kaur, MDHinsdale, IL 605211184624678

Common questions

What is James Ralph Clark, M.D.'s NPI number?

James Ralph Clark, M.D.'s National Provider Identifier (NPI) is 1588640650, issued on Dec 20, 2005. An NPI identifies a provider in billing; it is not a license.

Where is James Ralph Clark, M.D. located?

The NPPES record lists a practice address at 3825 Highland Ave, Downers Grove, IL, 60515. Phone: (630) 434-9312. Providers update this record themselves, so call before visiting.

How can I verify James Ralph Clark, M.D.'s license?

Search the Illinois Department of Financial and Professional Regulation at https://idfpr.illinois.gov/checklicense.html. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.

How much does James Ralph Clark, M.D. prescribe under Medicare Part D?

In 2024, James Ralph Clark, M.D. had 889 Medicare Part D claims for 376 beneficiaries; the average among gastroenterology physician prescribers was 811. Part D covers Medicare prescriptions only.

Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.

Written with AI tools from the named public files; every figure is computed from those files (how it is made).

Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.