MARK GEOFFERY STEIN M.D.
NPI 1265478564
Radiology - Diagnostic Radiology in Santa Ana, CA
About Mark Geoffery Stein M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MARK GEOFFERY STEIN M.D. (NPI 1265478564) is an individual diagnostic radiology provider in Santa Ana, California, licensed in California (A38805) and active in the NPI registry since June 2006. He is enrolled in Medicare PECOS and is a graduate of Other (1978).
NPPES Registry Identity
Specialties & Licenses 3
Other Identifiers 3
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
Mark Geoffery Stein 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
12Medicare enrollment records show Mark Stein reassigns Medicare billing to 12 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Orange, CA 92868
- Reassigned Medicare billing, California enrollment
- 202 clinicians in this Medicare group
Anaheim, CA 92801
- Reassigned Medicare billing, California enrollment
- Also billed through NPI 1093998122 (California), NPI 1649599085 (California)
- 349 clinicians in this Medicare group
Los Angeles, CA 90025
- Reassigned Medicare billing, California enrollment
- 311 clinicians in this Medicare group
Encino, CA 91436
- Reassigned Medicare billing, California enrollment
- 329 clinicians in this Medicare group
Palm Desert, CA 92260
- Reassigned Medicare billing, California enrollment
- 278 clinicians in this Medicare group
Fresno, CA 93710
- Reassigned Medicare billing, California enrollment
- 232 clinicians in this Medicare group
Modesto, CA 95350
- Reassigned Medicare billing, California enrollment
- 219 clinicians in this Medicare group
Fremont, CA 94538
- Reassigned Medicare billing, California enrollment
- 238 clinicians in this Medicare group
Stockton, CA 95210
- Reassigned Medicare billing, California enrollment
- 219 clinicians in this Medicare group
San Francisco, CA 94118
- Reassigned Medicare billing, California enrollment
- 219 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 14
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 92705 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 17
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
SANTA ANA, CA 92705
SANTA ANA, CA 92705
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 Mark Stein's NPI number?
The NPI number for Mark Stein is 1265478564. It was assigned to this individual provider in the NPPES registry on June 22, 2006.
Where is Mark Stein located?
Mark Stein practices at 1100 N Tustin Ave Bldg. A, Santa Ana, CA 92705. The listed phone number is (714) 835-6055.
What is Mark Stein's specialty?
The primary specialty registered for this NPI is Radiology, specializing in Diagnostic Radiology, with taxonomy code 2085R0202X.
Is Mark Stein enrolled in Medicare?
Yes. Mark Stein 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 Mark Stein's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Mark Stein reassigns Medicare benefits to 12 organizations: Uc Regents (Orange, CA), Beverly Radiology Medical Group III (Anaheim, CA), Pronet Imaging Medical Group, Inc. (Los Angeles, CA), San Fernando Valley Interventional Radiology And Imaging Center (Encino, CA), Desert Advanced Imaging Medical Center (Palm Desert, CA) and 7 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 Mark Stein'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 Mark Stein was last updated on June 16, 2015. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 11 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.
# Mark Geoffery Stein, M.D. · NPI 1265478564
Diagnostic Radiology physician in Santa Ana, California. Individual provider, active in the CMS NPPES registry since June 22, 2006.
## Identity
- **NPI:** 1265478564 (Entity type: Individual)
- **Enumerated:** June 22, 2006
- **Primary specialty:** Radiology - Diagnostic Radiology · taxonomy 2085R0202X
- **State license:** A38805 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 1100 N TUSTIN AVE, BLDG. A, Santa Ana, CA 92705-3509
- **Phone:** (714) 835-6055 · **Fax:** (714) 285-9084
## 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:** 12 organizations under Medicare reassignment (form CMS-855R): Uc Regents (NPI 1346298528, Orange, CA); Beverly Radiology Medical Group III (NPI 1972826774, Anaheim, CA); Pronet Imaging Medical Group, Inc. (NPI 1528099488, Los Angeles, CA); San Fernando Valley Interventional Radiology And Imaging Center (NPI 1942350889, Encino, CA); Desert Advanced Imaging Medical Center (NPI 1568416147, Palm Desert, CA); and 7 more · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 1978
## Record status
- **NPPES last updated:** June 16, 2015
- **Other identifiers:** Medicare UPIN E25279; Medicaid 00A388050 (CA); Medicare PIN WA38805C (CA)
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Source: [NPI Profile](https://npiprofile.com/npi/1265478564) · Data from the CMS NPPES public registry.