JOHN F GREHAN MD PHD
NPI 1275549784
Thoracic Surgery (Cardiothoracic Vascular Surgery) in Sioux Falls, SD
About John F Grehan Md Phd NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
JOHN F GREHAN MD PHD (NPI 1275549784) is an individual thoracic surgery (cardiothoracic vascular surgery) provider in Sioux Falls, South Dakota, licensed in South Dakota (13118) and active in the NPI registry since August 2006. He is enrolled in Medicare PECOS, is affiliated with Orange City Area Health System, and maintains a secondary practice location in St Paul.
NPPES Registry Identity
Specialties & Licenses
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
John F Grehan Md Phd 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 Grehan reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Sioux Falls, SD 57105
- Reassigned Medicare billing, South Dakota enrollment
- 826 clinicians in this Medicare group
Lamberton, MN 56152
- Reassigned Medicare billing, Minnesota enrollment
- 3,733 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 10
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 2
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Orange City Area Health System
Critical Access Hospitals · Orange City, IASanford Usd Medical Center
Acute Care Hospitals · Sioux Falls, SDPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 57105 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.
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 Grehan's NPI number?
The NPI number for John Grehan is 1275549784. It was assigned to this individual provider in the NPPES registry on August 1, 2006.
Where is John Grehan located?
John Grehan practices at 1301 W 18th St, Sioux Falls, SD 57105. The listed phone number is (605) 312-2100.
What is John Grehan's specialty?
The primary specialty registered for this NPI is Thoracic Surgery (Cardiothoracic Vascular Surgery) with taxonomy code 208G00000X.
Is John Grehan enrolled in Medicare?
Yes. John Grehan 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 Grehan's services?
According to the CMS Revalidation Reassignment List (October 2026 release), John Grehan reassigns Medicare benefits to 2 organizations: Sanford Clinic (Sioux Falls, SD) and Allina Health System (Lamberton, MN). 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 Grehan's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does John Grehan accept?
Health plans from Sanford Health Plan, Security Health Plan, Wellmark Health Plan of Iowa, Inc. and Wellmark of South Dakota, Inc. list John Grehan 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 Grehan affiliated with any hospitals?
According to CMS data, John Grehan is affiliated with Orange City Area Health System and Sanford Usd Medical Center.
When was this NPI record last updated?
The NPPES record for John Grehan was last updated on April 9, 2022. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 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.
# John F Grehan, MD PHD · NPI 1275549784
Thoracic Surgery (Cardiothoracic Vascular Surgery) physician in Sioux Falls, South Dakota. Individual provider, active in the CMS NPPES registry since August 1, 2006.
## Identity
- **NPI:** 1275549784 (Entity type: Individual)
- **Enumerated:** August 1, 2006
- **Primary specialty:** Thoracic Surgery (Cardiothoracic Vascular Surgery) · taxonomy 208G00000X
- **State license:** 13118 (South Dakota)
- **Sole proprietor:** No
## Practice location
- **Address:** 1301 W 18TH ST, Sioux Falls, SD 57105-0401
- **Phone:** (605) 312-2100
## 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): Sanford Clinic (NPI 1144259052, Sioux Falls, SD); Allina Health System (NPI 1467090159, Lamberton, MN) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** University Of Minnesota Medical School, class of 1995
## Record status
- **NPPES last updated:** April 9, 2022
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Source: [NPI Profile](https://npiprofile.com/npi/1275549784) · Data from the CMS NPPES public registry.