MICHAEL L MAHACEK MD
NPI 1922021484
Radiology - Radiation Oncology in Grand Rapids, MI
About Michael L Mahacek Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MICHAEL L MAHACEK MD (NPI 1922021484) is an individual radiation oncology provider in Grand Rapids, Michigan, licensed in Michigan (053126) and active in the NPI registry since July 2006. He is enrolled in Medicare PECOS, is affiliated with Spectrum Health United Hospital, and maintains a secondary practice location in Grand Rapids.
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Location 1
Other Identifiers 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
Michael L Mahacek Md 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 Reassignment
Medicare enrollment records show Michael Mahacek reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Grand Rapids, MI 49503
- Reassigned Medicare billing, Michigan enrollment
- 10 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 22
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.
Spectrum Health United Hospital
Acute Care Hospitals · Greenville, MISpectrum Health
Acute Care Hospitals · Grand Rapids, MIHolland Community Hospital
Acute Care Hospitals · Holland, MICorewell Health Big Rapids Hospital
Acute Care Hospitals · Big Rapids, MICorewell Health Reed City Hospital
Critical Access Hospitals · Reed City, MIPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 49503 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.
GRAND RAPIDS, MI 49503
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 Michael Mahacek's NPI number?
The NPI number for Michael Mahacek is 1922021484. It was assigned to this individual provider in the NPPES registry on July 25, 2006.
Where is Michael Mahacek located?
Michael Mahacek practices at 100 Michigan St NE, Grand Rapids, MI 49503. The listed phone number is (616) 391-1830.
What is Michael Mahacek's specialty?
The primary specialty registered for this NPI is Radiology, specializing in Radiation Oncology, with taxonomy code 2085R0001X.
Is Michael Mahacek enrolled in Medicare?
Yes. Michael Mahacek 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 organization bills Medicare for Michael Mahacek's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Michael Mahacek reassigns Medicare benefits to Radiation Oncology Centers PC (Grand Rapids, MI). 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 Michael Mahacek's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Michael Mahacek accept?
Health plans from Ambetter Health, Ambetter from Buckeye Health Plan, Ambetter from Meridian, Blue Care Network of Michigan and Blue Cross Blue Shield of Michigan Mutual Insurance Company and 1 other insurer list Michael Mahacek 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 Michael Mahacek affiliated with any hospitals?
According to CMS data, Michael Mahacek is affiliated with Spectrum Health United Hospital, Spectrum Health, Holland Community Hospital, Corewell Health Big Rapids Hospital and Corewell Health Reed City Hospital.
When was this NPI record last updated?
The NPPES record for Michael Mahacek was last updated on December 9, 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.