John Caleb Grenn, M.D.
NPI 1225569635ActiveIndividual· Internal Medicine· Corpus Christi, TX
Internal Medicine (M.D.) in Corpus Christi, Texas, trained at University of Mississippi School of Medicine (class of 2017). In 2024 Medicare paid $39,805 for 144 patients, and Part D covered 227 of their prescriptions, 86% of them generic. Abbvie Inc. was the largest of 3 companies reporting payments in 2025, $142.10 in all, mostly food and beverage.
Overview
| NPI | 1225569635 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | No |
| NPI issued | Mar 27, 2017 |
| Last updated in NPPES | Oct 7, 2026 |
| Certified by provider | Oct 7, 2026 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine Primary | 207R00000X | V9000 | TX |
| Hospitalist | 208M00000X | V9000 | TX |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 11, 2026 | No match | — |
| New York OMIG · Nov 11, 2026 | No match | — |
| Ohio Medicaid · Nov 11, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 11, 2026 | No match | — |
| Washington HCA · Nov 11, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Pediatric Medicine (MS); Practitioner - Internal Medicine (TX) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 144 |
|---|---|
| Services billed | 505 across 8 procedure codes |
| Paid by Medicare | $39,805 |
Part D prescriptions in 2024
| Prescriptions (claims) | 227 · 410 30-day fills |
|---|---|
| Patients | 58 |
| Total drug cost | $16,497 |
| Generic share | 86% of claims |
Education and affiliations
| Medical school | University of Mississippi School of Medicine |
|---|---|
| Graduation year | 2017 |
| Medicare specialty | Internal Medicine |
Medical group
- Hha Hospital Medicine of Texas PLLCHuntsville, TX · 30 clinicians
Hospital affiliation
- Corpus Christi Medical Center,theCorpus Christi, TX
Industry payments (Open Payments)
- 2025$142.10 · 6 payments from 3 companies
- 2024$141.46 · 6 payments from 4 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Abbvie Inc. | $76.51 | 3 |
| Pfizer Inc. | $43.12 | 2 |
| Mallinckrodt Hospital Products Inc. | $22.47 | 1 |
What the 2025 payments were for
- Food and Beverage$142.10 · 6 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 149 internal medicine physicians in Corpus Christi · All internal medicine physicians in Texas