John Caleb Grenn, M.D.
Internal Medicine Physician · Corpus Christi, TX
John Caleb Grenn, M.D. is an internal medicine physician with a practice address in Corpus Christi, Texas, and NPI 1225569635, issued on Mar 27, 2017. Check the license (Texas V9000, as entered in NPPES) on the Texas Medical Board; the Medicare figures below come from public CMS files.
- Name
- John Caleb Grenn
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- V9000 TX
Self-reported in NPPES; status is on the state search - Practice location
- 3315 S Alameda St, Corpus Christi, TX 78411
- Phone
- (877) 832-2652
- Enumerated
- Mar 27, 2017
- Record last updated
- Sep 9, 2025
- Fax
- (877) 454-6896
- Medicare enrollment
- Enrolled (PECOS I20210719001587); accepts Medicare assignment
- Medical or professional school
- University Of Mississippi School Of Medicine, 2017
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 9,175 in Texas → Look up another NPI →
Also registered at 3315 S Alameda St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify John Caleb Grenn in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersTexas Medical Board
Search for license V9000Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
93% fewer Medicare Part D claims than the average internal medicine physician in 2024
227 Medicare Part D claims for 58 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 14% of claims.
Most prescribed
- Nifedipine Er17 claims
- Atorvastatin Calcium16 claims
- Amlodipine Besylate11 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): 69.8 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: $141.46
6 payments; by number, the most common kind was food and beverage; the largest payer was Alexion Pharmaceuticals, Inc. The 50,334 providers of this specialty with any payment received $1,303.06 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 2 group practices
- Hha Hospital Medicine OF Texas PLLCCorpus Christi, TX
- State OF Mississippi-University OF Mississippi Medical CenterJackson, MS
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
John Caleb Grenn among 9,175 internal medicine physician records in Texas
John Caleb Grenn, M.D. is one of 9,175 internal medicine physician records with a practice address in Texas. 82% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2017, is newer than 77% of them.
- NPI issued2017 · 77% of these records are older, 21% newer
- In a Medicare fileYes · 82% of these records are
- In the CMS Doctors and Clinicians fileYes · 66% of these records are
- Graduated2017 · median 2004 among the 6,088 with a school on file
- Record last updated2025 · 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 207R00000X and a Texas practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
99 internal medicine physician records list a practice address in Corpus Christi
They are 99 of the 5,600 NPPES records with a practice address in Corpus Christi, and 9,175 internal medicine physician records in Texas.
All 9,175 in Texas → Every provider in Corpus Christi → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Fatima Bashir, M.D.Corpus Christi, TX 784111093000671
- Johanna Daugherty, M.D.Corpus Christi, TX 784111396058392
- Surendra Dawani, MDCorpus Christi, TX 784111215902432
- Priyank Dhar, MDCorpus Christi, TX 784111285014175
- Natalie Harris, D.O.Corpus Christi, TX 784111003004201
- David Heredia, MDCorpus Christi, TX 784111104980408
- Pavlo Kodak, M.D.Corpus Christi, TX 784111790113918
- Cyril Owusu-Boakye, M.D.Corpus Christi, TX 784111851530455
Common questions
What is John Caleb Grenn, M.D.'s NPI number?
John Caleb Grenn, M.D.'s National Provider Identifier (NPI) is 1225569635, issued on Mar 27, 2017. An NPI identifies a provider in billing; it is not a license.
Where is John Caleb Grenn, M.D. located?
The NPPES record lists a practice address at 3315 S Alameda St, Corpus Christi, TX, 78411. Phone: (877) 832-2652. Providers update this record themselves, so call before visiting.
How can I verify John Caleb Grenn, M.D.'s license?
NPPES lists Texas license number V9000, 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 John Caleb Grenn, M.D. prescribe under Medicare Part D?
In 2024, John Caleb Grenn, M.D. had 227 Medicare Part D claims for 58 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
What is John Caleb Grenn, M.D.'s MIPS final score?
The 2023 MIPS final score is 69.8 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.