DR. WILLIAM HAYES ARMSTRONG MD
NPI 1245960293
Emergency Medicine in Los Angeles, CA
About Dr. William Hayes Armstrong Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. WILLIAM HAYES ARMSTRONG MD (NPI 1245960293) is an individual emergency medicine provider in Los Angeles, California, licensed in California (A200987) and active in the NPI registry since June 2022. He is enrolled in Medicare PECOS, maintains a secondary practice location in Richmond, and is a graduate of Virginia Commonwealth University, School Of Medicine (2022).
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Location 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. William Hayes Armstrong 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 Reassignments
2Medicare enrollment records show William Armstrong reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Los Angeles, CA 90015
- Reassigned Medicare billing, California enrollment
- 169 clinicians in this Medicare group
Northridge, CA 91325
- Reassigned Medicare billing, California enrollment
- 137 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 90015 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.
LOS ANGELES, CA 90015
LOS ANGELES, CA 90015
LOS ANGELES, CA 90015
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 William Armstrong's NPI number?
The NPI number for William Armstrong is 1245960293. It was assigned to this individual provider in the NPPES registry on June 13, 2022.
Where is William Armstrong located?
William Armstrong practices at 1401 S Grand Ave, Los Angeles, CA 90015. The listed phone number is (213) 748-2411.
What is William Armstrong's specialty?
The primary specialty registered for this NPI is Emergency Medicine with taxonomy code 207P00000X.
Is William Armstrong enrolled in Medicare?
Yes. William Armstrong 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 William Armstrong's services?
According to the CMS Revalidation Reassignment List (October 2026 release), William Armstrong reassigns Medicare benefits to 2 organizations: Golden State Emergency Physicians Inc (Los Angeles, CA) and Ridgeline Emergency Physicians Medical Group, Inc. (Northridge, 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 William Armstrong'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 William Armstrong was last updated on June 29, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 15 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. William Hayes Armstrong, MD · NPI 1245960293
Emergency Medicine physician in Los Angeles, California. Individual provider, active in the CMS NPPES registry since June 13, 2022.
## Identity
- **NPI:** 1245960293 (Entity type: Individual)
- **Enumerated:** June 13, 2022
- **Primary specialty:** Emergency Medicine · taxonomy 207P00000X
- **State license:** A200987 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 1401 S GRAND AVE, Los Angeles, CA 90015-3010
- **Phone:** (213) 748-2411
## 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): Golden State Emergency Physicians Inc (NPI 1770886558, Los Angeles, CA); Ridgeline Emergency Physicians Medical Group, Inc. (NPI 1972953230, Northridge, CA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Virginia Commonwealth University, School Of Medicine, class of 2022
## Record status
- **NPPES last updated:** June 29, 2025
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Source: [NPI Profile](https://npiprofile.com/npi/1245960293) · Data from the CMS NPPES public registry.