MARGARET M GRENISEN MD
NPI 1447231766
Family Medicine in La Crosse, WI
About Margaret M Grenisen Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MARGARET M GRENISEN MD (NPI 1447231766) is an individual family medicine provider in La Crosse, Wisconsin, licensed in Wisconsin (32890) and active in the NPI registry since November 2005. She is enrolled in Medicare PECOS.
NPPES Registry Identity
Specialties & Licenses
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare (PECOS)
Margaret M Grenisen Md is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Medicare Billing Reassignment
Medicare enrollment records show Margaret Grenisen reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
La Crosse, WI 54601
- Reassigned Medicare billing, Wisconsin enrollment
- 1,003 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
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.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 54601 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.
LA CROSSE, WI 54601
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 Margaret Grenisen's NPI number?
The NPI number for Margaret Grenisen is 1447231766. It was assigned to this individual provider in the NPPES registry on November 14, 2005.
Where is Margaret Grenisen located?
Margaret Grenisen practices at 800 West Ave S, La Crosse, WI 54601. The listed phone number is (608) 392-9891.
What is Margaret Grenisen's specialty?
The primary specialty registered for this NPI is Family Medicine with taxonomy code 207Q00000X.
Is Margaret Grenisen enrolled in Medicare?
Yes. Margaret Grenisen is registered in the Medicare PECOS enrollment system.
Which organization bills Medicare for Margaret Grenisen's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Margaret Grenisen reassigns Medicare benefits to Mayo Clinic Health System-Southwest Wisconsin Region, Inc. (La Crosse, WI). The 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 Margaret Grenisen's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
When was this NPI record last updated?
The NPPES record for Margaret Grenisen was last updated on June 15, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 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.
# Margaret M Grenisen, MD · NPI 1447231766
Family Medicine physician in La Crosse, Wisconsin. Individual provider, active in the CMS NPPES registry since November 14, 2005.
## Identity
- **NPI:** 1447231766 (Entity type: Individual)
- **Enumerated:** November 14, 2005
- **Primary specialty:** Family Medicine · taxonomy 207Q00000X
- **State license:** 32890 (Wisconsin)
- **Sole proprietor:** No
## Practice location
- **Address:** 800 WEST AVE S, La Crosse, WI 54601-8806
- **Phone:** (608) 392-9891
## Medicare
- **Medicare:** Enrolled in Medicare (PECOS)
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** Mayo Clinic Health System-Southwest Wisconsin Region, Inc. (NPI 1629056049, La Crosse, WI), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
## Record status
- **NPPES last updated:** June 15, 2026
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Source: [NPI Profile](https://npiprofile.com/npi/1447231766) · Data from the CMS NPPES public registry.