JON WILLIAM MARES D.O.
NPI 1023375300
Internal Medicine - Nephrology in Covington, LA
About Jon William Mares D.o. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
JON WILLIAM MARES D.O. (NPI 1023375300) is an individual nephrology provider in Covington, Louisiana, licensed in Illinois (036.151545) and active in the NPI registry since April 2012. He is enrolled in Medicare PECOS, is affiliated with North Oaks Medical Center, and is a graduate of Kansas City University Of Physicians And Surgeons (2012).
NPPES Registry Identity
Specialties & Licenses 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
Jon William Mares D.o. 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
3Medicare enrollment records show Jon Mares reassigns Medicare billing to 3 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Covington, LA 70433
- Reassigned Medicare billing, Louisiana enrollment
- 30 clinicians in this Medicare group
Covington, LA 70433
- Reassigned Medicare billing, Louisiana enrollment
- 2 clinicians in this Medicare group
Gulfport, MS 39501
- Reassigned Medicare billing, Mississippi enrollment
- 14 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.
North Oaks Medical Center
Acute Care Hospitals · Hammond, LAPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 70433 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
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.
COVINGTON, LA 70433
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 Jon Mares's NPI number?
The NPI number for Jon Mares is 1023375300. It was assigned to this individual provider in the NPPES registry on April 11, 2012.
Where is Jon Mares located?
Jon Mares practices at 1970 N Highway 190, Covington, LA 70433. The listed phone number is (985) 867-8585.
What is Jon Mares's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Nephrology, with taxonomy code 207RN0300X.
Is Jon Mares enrolled in Medicare?
Yes. Jon Mares 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 Jon Mares's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Jon Mares reassigns Medicare benefits to 3 organizations: Nni Covington LLC (Covington, LA), Jwm Renal, LLC (Covington, LA) and South Mississippi Nephrology, PLLC (Gulfport, 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 Jon Mares's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Jon Mares accept?
Health plans from Ambetter Health, Ambetter from Arkansas Health & Wellness, Ambetter from Louisiana Healthcare Connections, Ambetter from Superior HealthPlan and Cigna Healthcare and 1 other insurer list Jon Mares 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 Jon Mares affiliated with any hospitals?
According to CMS data, Jon Mares is affiliated with North Oaks Medical Center.
When was this NPI record last updated?
The NPPES record for Jon Mares was last updated on September 17, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 13 months 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.
# Jon William Mares, D.O. · NPI 1023375300
Nephrology physician in Covington, Louisiana. Individual provider, active in the CMS NPPES registry since April 11, 2012.
## Identity
- **NPI:** 1023375300 (Entity type: Individual)
- **Enumerated:** April 11, 2012
- **Primary specialty:** Internal Medicine - Nephrology · taxonomy 207RN0300X
- **State license:** 036.151545 (Illinois)
- **Sole proprietor:** No
## Practice location
- **Address:** 1970 N HIGHWAY 190, Covington, LA 70433-5364
- **Phone:** (985) 867-8585 · **Fax:** (985) 867-3644
## 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:** 3 organizations under Medicare reassignment (form CMS-855R): Nni Covington LLC (NPI 1972060168, Covington, LA); Jwm Renal, LLC (NPI 1790665396, Covington, LA); South Mississippi Nephrology, PLLC (NPI 1134168081, Gulfport, MS) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Kansas City University Of Physicians And Surgeons, class of 2012
## Record status
- **NPPES last updated:** September 17, 2025
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Source: [NPI Profile](https://npiprofile.com/npi/1023375300) · Data from the CMS NPPES public registry.