CATHERINE LOUISE ASH M.D.
NPI 1861874059
Internal Medicine in Edwardsville, IL
About Catherine Louise Ash M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
CATHERINE LOUISE ASH M.D. (NPI 1861874059) is an individual internal medicine provider in Edwardsville, Illinois, licensed in Illinois (036177442) and active in the NPI registry since June 2015. She is enrolled in Medicare PECOS, is affiliated with Alton Memorial Hospital, and maintains a secondary practice location in Saint Louis.
NPPES Registry Identity
Specialties & Licenses
Other Names 1
Secondary Practice Location 1
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
Catherine Louise Ash 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
8Medicare enrollment records show Catherine Ash reassigns Medicare billing to 8 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Saint Louis, MO 63141
- Reassigned Medicare billing, Missouri enrollment
- 326 clinicians in this Medicare group
Saint Louis, MO 63141
- Reassigned Medicare billing, Missouri enrollment
- 744 clinicians in this Medicare group
Saint Louis, MO 63141
- Reassigned Medicare billing, Missouri enrollment
- 435 clinicians in this Medicare group
Saint Louis, MO 63141
- Reassigned Medicare billing, Illinois enrollment
- 507 clinicians in this Medicare group
Saint Louis, MO 63128
- Reassigned Medicare billing, Missouri enrollment
- Medicare enrollment name: St Anthonys Physician Organization Hospitalist Services Lc
- 340 clinicians in this Medicare group
Festus, MO 63028
- Reassigned Medicare billing, Missouri enrollment
- 299 clinicians in this Medicare group
Winfield, MO 63389
- Reassigned Medicare billing, Missouri enrollment
- 229 clinicians in this Medicare group
Washington, MO 63090
- Reassigned Medicare billing, Missouri enrollment
- 261 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 9
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 5
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Alton Memorial Hospital
Acute Care Hospitals · Alton, ILMemorial Hospital
Acute Care Hospitals · Belleville, ILMercy Hospital St Louis
Acute Care Hospitals · Saint Louis, MOMercy Hospital South
Acute Care Hospitals · Saint Louis, MOChristian Hospital Northeast
Acute Care Hospitals · Saint Louis, MOPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 62025 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Referred Medical Equipment & Supplies CMS DME claims 2
Durable medical equipment, devices and supplies this provider ordered from DME suppliers for patients, from Medicare fee-for-service claims.
Other Providers at the Same Location NPPES 13
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
EDWARDSVILLE, IL 62025
EDWARDSVILLE, IL 62025
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 Catherine Ash's NPI number?
The NPI number for Catherine Ash is 1861874059. It was assigned to this individual provider in the NPPES registry on June 24, 2015. The provider is also known as Catherine Louise Duncan.
Where is Catherine Ash located?
Catherine Ash practices at 2122 Troy Rd Ste 130, Edwardsville, IL 62025. The listed phone number is (618) 800-4500.
What is Catherine Ash's specialty?
The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.
Is Catherine Ash enrolled in Medicare?
Yes. Catherine Ash 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 Catherine Ash's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Catherine Ash reassigns Medicare benefits to 8 organizations: Mercy Clinic Adult Hospitalists - St. Louis, LLC (Saint Louis, MO), Mercy Clinic East Communities (Saint Louis, MO), Mercy Hospitals East Communities (Saint Louis, MO), Fairview Heights Medical Group, Sc (Saint Louis, MO), St Anthonys Physician Organization Hospitalist Services, L.C. (Saint Louis, MO) and 3 more organizations, listed in the Medicare section above. 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 Catherine Ash's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Catherine Ash accept?
Health plans from UnitedHealthcare list Catherine Ash 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 Catherine Ash affiliated with any hospitals?
According to CMS data, Catherine Ash is affiliated with Alton Memorial Hospital, Memorial Hospital, Mercy Hospital St Louis, Mercy Hospital South and Christian Hospital Northeast.
When was this NPI record last updated?
The NPPES record for Catherine Ash was last updated on December 18, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 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.
# Catherine Louise Ash, M.D. · NPI 1861874059
Internal Medicine physician in Edwardsville, Illinois. Individual provider, active in the CMS NPPES registry since June 24, 2015.
## Identity
- **NPI:** 1861874059 (Entity type: Individual)
- **Enumerated:** June 24, 2015
- **Primary specialty:** Internal Medicine · taxonomy 207R00000X
- **State license:** 036177442 (Illinois)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 2122 TROY RD STE 130, Edwardsville, IL 62025-2540
- **Phone:** (618) 800-4500 · **Fax:** (618) 800-4501
## 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:** 8 organizations under Medicare reassignment (form CMS-855R): Mercy Clinic Adult Hospitalists - St. Louis, LLC (NPI 1841235108, Saint Louis, MO); Mercy Clinic East Communities (NPI 1043574940, Saint Louis, MO); Mercy Hospitals East Communities (NPI 1851431738, Saint Louis, MO); Fairview Heights Medical Group, Sc (NPI 1811392210, Saint Louis, MO); St Anthonys Physician Organization Hospitalist Services, L.C. (NPI 1407216336, Saint Louis, MO); and 3 more · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Saint Louis University School Of Medicine, class of 2015
## Record status
- **NPPES last updated:** December 18, 2025
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Source: [NPI Profile](https://npiprofile.com/npi/1861874059) · Data from the CMS NPPES public registry.