DR. JAMES SAEYUNG AHN M.D.
NPI 1588641963
Anesthesiology in Corona, CA
About Dr. James Saeyung Ahn M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. JAMES SAEYUNG AHN M.D. (NPI 1588641963) is an individual anesthesiology provider in Corona, California, licensed in California (G84344) and active in the NPI registry since December 2005. He is enrolled in Medicare PECOS, maintains a secondary practice location in Duarte, and is a graduate of Other (1990).
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Location 1
Other Identifiers 1
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
Dr. James Saeyung Ahn 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
6Medicare enrollment records show James Ahn reassigns Medicare billing to 6 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Corona, CA 92882
- Reassigned Medicare billing, California enrollment
- 70 clinicians in this Medicare group
Anaheim, CA 92807
- Reassigned Medicare billing, California enrollment
- 488 clinicians in this Medicare group
Anaheim, CA 92807
- Reassigned Medicare billing, California enrollment
- 13,921 clinicians in this Medicare group
Orange, CA 92868
- Reassigned Medicare billing, California enrollment
- 420 clinicians in this Medicare group
Duarte, CA 91010
- Reassigned Medicare billing, California enrollment
- 1,335 clinicians in this Medicare group
- Reassigned Medicare billing, California enrollment
- 420 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.
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.
CORONA, CA 92882
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 James Ahn's NPI number?
The NPI number for James Ahn is 1588641963. It was assigned to this individual provider in the NPPES registry on December 28, 2005.
Where is James Ahn located?
James Ahn practices at 800 S Main St, Corona, CA 92882. The listed phone number is (951) 737-4343.
What is James Ahn's specialty?
The primary specialty registered for this NPI is Anesthesiology with taxonomy code 207L00000X.
Is James Ahn enrolled in Medicare?
Yes. James Ahn 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 James Ahn's services?
According to the CMS Revalidation Reassignment List (October 2026 release), James Ahn reassigns Medicare benefits to 6 organizations: Corona Anesthesia Group, Inc. (Corona, CA), First Choice Physician Partners (Anaheim, CA), Southern California Permanente Medical Group (Anaheim, CA), Regents Of The University Of (Orange, CA), City Of Hope Medical Foundation (Duarte, CA) and 1 more organization, 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 James Ahn'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 James Ahn was last updated on May 8, 2024. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 2 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.
# Dr. James Saeyung Ahn, M.D. · NPI 1588641963
Anesthesiology physician in Corona, California. Individual provider, active in the CMS NPPES registry since December 28, 2005.
## Identity
- **NPI:** 1588641963 (Entity type: Individual)
- **Enumerated:** December 28, 2005
- **Primary specialty:** Anesthesiology · taxonomy 207L00000X
- **State license:** G84344 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 800 S MAIN ST, Corona, CA 92882-3420
- **Phone:** (951) 737-4343
## 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:** 6 organizations under Medicare reassignment (form CMS-855R): Corona Anesthesia Group, Inc. (NPI 1558865840, Corona, CA); First Choice Physician Partners (NPI 1083966691, Anaheim, CA); Southern California Permanente Medical Group (NPI 1952333460, Anaheim, CA); Regents Of The University Of (NPI 1487602546, Orange, CA); City Of Hope Medical Foundation (NPI 1871886366, Duarte, CA); and 1 more · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 1990
## Record status
- **NPPES last updated:** May 8, 2024
- **Other identifiers:** Medicaid 00G843440 (CA)
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Source: [NPI Profile](https://npiprofile.com/npi/1588641963) · Data from the CMS NPPES public registry.