MARY KAY NISSEN
NPI 1659604403
Nurse Practitioner in Sioux City, IA
About Mary Kay Nissen NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MARY KAY NISSEN (NPI 1659604403) is an individual nurse practitioner in Sioux City, Iowa, licensed in Iowa (A-076138) and active in the NPI registry since September 2009. She is enrolled in Medicare PECOS, is affiliated with Shenandoah Medical Center, and is a graduate of Other (2009).
NPPES Registry Identity
Specialties & Licenses
Other Names 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
Mary Kay Nissen 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 Mary Nissen reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Rock Rapids, IA 51246
- Reassigned Medicare billing, South Dakota enrollment
- 1,277 clinicians in this Medicare group
Tabor, IA 51653
- Reassigned Medicare billing, Iowa enrollment
- 91 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.
Hospital Affiliations CMS Care Compare
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Shenandoah Medical Center
Critical Access Hospitals · Shenandoah, IAPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 51104 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 3
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
SIOUX CITY, IA 51104
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 Mary Nissen's NPI number?
The NPI number for Mary Nissen is 1659604403. It was assigned to this individual provider in the NPPES registry on September 11, 2009. The provider is also known as Mary Kay Studer Arnp-Bc.
Where is Mary Nissen located?
Mary Nissen practices at 3303 Rebecca St, Sioux City, IA 51104. The listed phone number is (712) 279-5458.
What is Mary Nissen's specialty?
The primary specialty registered for this NPI is Nurse Practitioner with taxonomy code 363L00000X.
Is Mary Nissen enrolled in Medicare?
Yes. Mary Nissen 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 Mary Nissen's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Mary Nissen reassigns Medicare benefits to 2 organizations: Avera Mckennan (Rock Rapids, IA) and Shenandoah Medical Center (Tabor, IA). 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 Mary Nissen's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Mary Nissen accept?
Health plans from Ambetter Health, Ambetter Health of Delaware, Ambetter from Arkansas Health & Wellness, Ambetter from Sunflower Health Plan and Ambetter of Oklahoma and 3 other insurers list Mary Nissen 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 Mary Nissen affiliated with any hospitals?
According to CMS data, Mary Nissen is affiliated with Shenandoah Medical Center.
When was this NPI record last updated?
The NPPES record for Mary Nissen was last updated on October 3, 2023. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 3 years 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.
# Mary Kay Nissen · NPI 1659604403
Nurse Practitioner physician in Sioux City, Iowa. Individual provider, active in the CMS NPPES registry since September 11, 2009.
## Identity
- **NPI:** 1659604403 (Entity type: Individual)
- **Enumerated:** September 11, 2009
- **Primary specialty:** Nurse Practitioner · taxonomy 363L00000X
- **State license:** A-076138 (Iowa)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 3303 REBECCA ST, Sioux City, IA 51104-2324
- **Phone:** (712) 279-5458
## 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): Avera Mckennan (NPI 1003389206, Rock Rapids, IA); Shenandoah Medical Center (NPI 1508487547, Tabor, IA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2009
## Record status
- **NPPES last updated:** October 3, 2023
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Source: [NPI Profile](https://npiprofile.com/npi/1659604403) · Data from the CMS NPPES public registry.