JOHN CALEB GRENN M.D.
NPI 1225569635
Internal Medicine in Corpus Christi, TX
About John Caleb Grenn M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
JOHN CALEB GRENN M.D. (NPI 1225569635) is an individual internal medicine provider in Corpus Christi, Texas, licensed in Texas (V9000) and active in the NPI registry since March 2017. He is enrolled in Medicare PECOS, is affiliated with Corpus Christi Medical Center,the, and maintains 2 additional practice locations.
NPPES Registry Identity
Specialties & Licenses 2
Secondary Practice Locations 2
Accepted Insurance
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
John Caleb Grenn M.d. is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignments
2Medicare enrollment records show John Grenn reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Huntsville, TX 77340
- Reassigned Medicare billing, Texas enrollment
- 44 clinicians in this Medicare group
Jackson, MS 39213
- Reassigned Medicare billing, Mississippi enrollment
- 1,932 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims 4
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Hospital Affiliations CMS Care Compare
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Corpus Christi Medical Center,the
Acute Care Hospitals · Corpus Christi, TXPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 78411 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Medicare Quality Performance CMS QPP · MIPS
Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
CORPUS CHRISTI, TX 78411
CORPUS CHRISTI, TX 78411
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is John Grenn's NPI number?
The NPI number for John Grenn is 1225569635. It was assigned to this individual provider in the NPPES registry on March 27, 2017.
Where is John Grenn located?
John Grenn practices at 3315 S Alameda St, Corpus Christi, TX 78411. The listed phone number is (877) 832-2652.
What is John Grenn's specialty?
The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.
Is John Grenn enrolled in Medicare?
Yes. John Grenn is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organizations bill Medicare for John Grenn's services?
According to the CMS Revalidation Reassignment List (October 2026 release), John Grenn reassigns Medicare benefits to 2 organizations: Hha Hospital Medicine Of Texas PLLC (Huntsville, TX) and State Of Mississippi- University Of Mississippi Medical Center (Jackson, MS). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for John Grenn's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does John Grenn accept?
Health plans from Ambetter Health, Ambetter from Arkansas Health & Wellness, Ambetter from Louisiana Healthcare Connections, Ambetter of Alabama and Ambetter of Tennessee and 1 other insurer list John Grenn as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
Is John Grenn affiliated with any hospitals?
According to CMS data, John Grenn is affiliated with Corpus Christi Medical Center,the.
When was this NPI record last updated?
The NPPES record for John Grenn was last updated on October 7, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 16 days ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# John Caleb Grenn, M.D. · NPI 1225569635
Internal Medicine physician in Corpus Christi, Texas. Individual provider, active in the CMS NPPES registry since March 27, 2017.
## Identity
- **NPI:** 1225569635 (Entity type: Individual)
- **Enumerated:** March 27, 2017
- **Primary specialty:** Internal Medicine · taxonomy 207R00000X
- **State license:** V9000 (Texas)
- **Sole proprietor:** No
## Practice location
- **Address:** 3315 S ALAMEDA ST, Corpus Christi, TX 78411-1820
- **Phone:** (877) 832-2652 · **Fax:** (877) 454-6896
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 2 organizations under Medicare reassignment (form CMS-855R): Hha Hospital Medicine Of Texas PLLC (NPI 1083489967, Huntsville, TX); State Of Mississippi- University Of Mississippi Medical Center (NPI 1194930693, Jackson, MS) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** University Of Mississippi School Of Medicine, class of 2017
## Record status
- **NPPES last updated:** October 7, 2026
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Source: [NPI Profile](https://npiprofile.com/npi/1225569635) · Data from the CMS NPPES public registry.