Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

John Caleb Grenn, MD

Individual provider Internal Medicine Physician · NPI 1225569635

John Caleb Grenn, MD practises Internal Medicine in Corpus Christi, Texas. Graduated from University of Mississippi School of Medicine in 2017, 9 years ago. Practices with Hha Hospital Medicine of Texas PLLC, a 27-clinician group, works from 3 locations and accepts Medicare assignment. Licensed in Texas.

Years since qualifying
9
Trained at
University of Mississippi School of Medicine
Licensed in
TX
In the registry since
2017
Specialties on file
2
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

3315 S Alameda St
Corpus Christi, TX 78411-1820
Phone: (877) 832-2652
Fax: (877) 454-6896
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (2)

  • 7101 S Padre Island Dr, Corpus Christi, TX 78412-4913 — (877) 832-2652
  • 301 University Blvd, Galveston, TX 77555-5302 — (409) 747-1883

Specialties & licences

Internal Medicine Physician (primary) Taxonomy 207R00000X · Licence V9000 (TX)
Hospitalist Physician Taxonomy 208M00000X · Licence V9000 (TX)

Record details

NPI number1225569635
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedMarch 27, 2017
Last updated in NPPESOctober 7, 2026
Certification dateOctober 7, 2026

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyINTERNAL MEDICINE
Medical schoolUNIVERSITY OF MISSISSIPPI SCHOOL OF MEDICINE
Graduated 2017 (9 years in practice)
Group practice Hha Hospital Medicine Of Texas Pllc — 27 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients144
Services billed 505 a service is one billed item, such as a visit, a test or a procedure
Average patient age67

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $142 6 payments · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

  • Corpus Christi Medical Center,The Hospital · Corpus Christi, TX

Colleagues at Hha Hospital Medicine of Texas PLLC

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 27 clinicians in the practice; 12 are shown here.

Other providers in Corpus Christi