DR. MICHAEL TIEU LOI DO
NPI 1861057556
Internal Medicine in Irvine, CA
About Dr. Michael Tieu Loi Do NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. MICHAEL TIEU LOI DO (NPI 1861057556) is an individual internal medicine provider in Irvine, California, licensed in California (20A22634) and active in the NPI registry since May 2019. He is enrolled in Medicare PECOS.
NPPES Registry Identity
Specialties & Licenses 2
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare (PECOS)
Dr. Michael Tieu Loi Do is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Medicare Billing Reassignments
3Medicare enrollment records show Michael Loi reassigns Medicare billing to 3 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Tustin, CA 92780
- Reassigned Medicare billing, California enrollment
- 2,052 clinicians in this Medicare group
Los Alamitos, CA 90720
- Reassigned Medicare billing, California enrollment
- 228 clinicians in this Medicare group
Moreno Valley, CA 92555
- Reassigned Medicare billing, California enrollment
- 111 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.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 92618 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
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 Michael Loi's NPI number?
The NPI number for Michael Loi is 1861057556. It was assigned to this individual provider in the NPPES registry on May 8, 2019.
Where is Michael Loi located?
Michael Loi practices at 11 Technology Dr, Irvine, CA 92618. The listed phone number is (949) 923-3200.
What is Michael Loi's specialty?
The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.
Is Michael Loi enrolled in Medicare?
Yes. Michael Loi is registered in the Medicare PECOS enrollment system.
Which organizations bill Medicare for Michael Loi's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Michael Loi reassigns Medicare benefits to 3 organizations: Healthcare Partners Affiliates Medical Group (Tustin, CA), Centers For Family Medicine Gp (Los Alamitos, CA) and Riverside Faculty Medical Group Inc (Moreno Valley, CA). 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 Michael Loi'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 Michael Loi was last updated on November 23, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 11 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.
# Dr. Michael Tieu Loi, DO · NPI 1861057556
Internal Medicine physician in Irvine, California. Individual provider, active in the CMS NPPES registry since May 8, 2019.
## Identity
- **NPI:** 1861057556 (Entity type: Individual)
- **Enumerated:** May 8, 2019
- **Primary specialty:** Internal Medicine · taxonomy 207R00000X
- **State license:** 20A22634 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 11 TECHNOLOGY DR, Irvine, CA 92618-2302
- **Phone:** (949) 923-3200
## Medicare
- **Medicare:** Enrolled in Medicare (PECOS)
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 3 organizations under Medicare reassignment (form CMS-855R): Healthcare Partners Affiliates Medical Group (NPI 1891981502, Tustin, CA); Centers For Family Medicine Gp (NPI 1467598243, Los Alamitos, CA); Riverside Faculty Medical Group Inc (NPI 1124032461, Moreno Valley, CA) · CMS Revalidation Reassignment List, October 2026 release
## Record status
- **NPPES last updated:** November 23, 2025
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Source: [NPI Profile](https://npiprofile.com/npi/1861057556) · Data from the CMS NPPES public registry.