Gerald Marshall Isbell, M.D.
Gastroenterology Physician · Dallas, TX
Gerald Marshall Isbell, M.D. is a gastroenterology physician with a practice address in Dallas, Texas, and NPI 1093774853, issued on Mar 21, 2006. Check the license (Texas H1289, as entered in NPPES) on the Texas Medical Board; the Medicare figures below come from public CMS files.
- Name
- Gerald Marshall Isbell
- Credential
- M.D.
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License number
- H1289 TX
Self-reported in NPPES; status is on the state search - Practice location
- 6201 Harry Hines Blvd, Dallas, TX 75390
- Phone
- (214) 633-5555
- Enumerated
- Mar 21, 2006
- Record last updated
- Mar 25, 2022
- Medicaid ID
- 126555503 TX
- Medicare enrollment
- Enrolled (PECOS I20070725000325); accepts Medicare assignment
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest gastroenterology physician records → All 1,478 in Texas → Look up another NPI →
Also registered at 6201 Harry Hines Blvd
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Gerald Marshall Isbell in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersTexas Medical Board
Search for license H1289Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
35% fewer Medicare Part D claims than the average gastroenterology physician in 2024
528 Medicare Part D claims for 201 beneficiaries, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D. Brand-name drugs were 24% of claims.
Most prescribed
- Pantoprazole Sodium100 claims
- Ondansetron Hcl57 claims
- Linzess51 claims
- Gavilyte-G35 claims
- Peg-3350 And Electrolytes25 claims
- Famotidine21 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.
The practice group's MIPS final score for 2023 (Medicare payment program): 74.6 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $60.24
3 payments; by number, the most common kind was food and beverage; the largest payer was Regeneron Healthcare Solutions, 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.
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
- University OF Texas Southwestern Medical Center AT DallasDallas, TX
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Gerald Marshall Isbell among 1,478 gastroenterology physician records in Texas
Gerald Marshall Isbell, M.D. is one of 1,478 gastroenterology physician records with a practice address in Texas. 89% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 14% of them.
- NPI issued2006 · 14% of these records are older, 51% newer
- In a Medicare fileYes · 89% of these records are
- In the CMS Doctors and Clinicians fileYes · 79% of these records are
- Graduated1982 · median 2003 among the 1,175 with a school on file
- Record last updated2022 · 53% 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 Texas practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Gastroenterology Physician providers in Texas
There are 1,478 gastroenterology physician records in Texas.
All 1,478 in Texas → Every provider in Dallas → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Jeffrey Browning, MDDallas, TX 753901871550285
- Lisa Casey, M.D.Dallas, TX 753901245279264
- Jennifer Cuthbert, MDDallas, TX 753901598850612
- John Fitz, MDDallas, TX 753901124087259
- Markus Goldschmiedt, M.D.Dallas, TX 753901760441604
- Homer Herlong, M.D.Dallas, TX 753901699725366
- Jay Horton, MDDallas, TX 753901104866458
- John Kwon, MDDallas, TX 753901841232741
Common questions
What is Gerald Marshall Isbell, M.D.'s NPI number?
Gerald Marshall Isbell, M.D.'s National Provider Identifier (NPI) is 1093774853, issued on Mar 21, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Gerald Marshall Isbell, M.D. located?
The NPPES record lists a practice address at 6201 Harry Hines Blvd, Dallas, TX, 75390. Phone: (214) 633-5555. Providers update this record themselves, so call before visiting.
How can I verify Gerald Marshall Isbell, M.D.'s license?
NPPES lists Texas license number H1289, as entered by the provider. Search the Texas Medical Board at https://profile.tmb.state.tx.us/Search.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Gerald Marshall Isbell, M.D. prescribe under Medicare Part D?
In 2024, Gerald Marshall Isbell, M.D. had 528 Medicare Part D claims for 201 beneficiaries; the average among gastroenterology physician prescribers was 811. Part D covers Medicare prescriptions only.
What is Gerald Marshall Isbell, M.D.'s MIPS final score?
The 2023 MIPS final score is 74.6 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
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.
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.