WILLIAM R SHIRER M.D.
NPI 1912438854
Anesthesiology in San Jose, CA
About William R Shirer M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
WILLIAM R SHIRER M.D. (NPI 1912438854) is an individual anesthesiology provider in San Jose, California, licensed in California (A157296) and active in the NPI registry since March 2017. He is enrolled in Medicare PECOS, maintains 2 additional practice locations, and is a graduate of Stanford University School Of Medicine (2017).
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Locations 2
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
William R Shirer 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
2Medicare enrollment records show William Shirer reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Santa Clara, CA 95051
- Reassigned Medicare billing, California enrollment
- 20,078 clinicians in this Medicare group
Manteca, CA 95336
- Reassigned Medicare billing, California enrollment
- 488 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.
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 William Shirer's NPI number?
The NPI number for William Shirer is 1912438854. It was assigned to this individual provider in the NPPES registry on March 22, 2017.
Where is William Shirer located?
William Shirer practices at 250 Hospital Pkwy, San Jose, CA 95119. The listed phone number is (408) 972-3000.
What is William Shirer's specialty?
The primary specialty registered for this NPI is Anesthesiology with taxonomy code 207L00000X.
Is William Shirer enrolled in Medicare?
Yes. William Shirer 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 Shirer's services?
According to the CMS Revalidation Reassignment List (October 2026 release), William Shirer reassigns Medicare benefits to 2 organizations: Permanente Medical Group Inc (Santa Clara, CA) and First Choice Physician Partners (Manteca, 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 Shirer'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 Shirer was last updated on August 1, 2022. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 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.
# William R Shirer, M.D. · NPI 1912438854
Anesthesiology physician in San Jose, California. Individual provider, active in the CMS NPPES registry since March 22, 2017.
## Identity
- **NPI:** 1912438854 (Entity type: Individual)
- **Enumerated:** March 22, 2017
- **Primary specialty:** Anesthesiology · taxonomy 207L00000X
- **State license:** A157296 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 250 HOSPITAL PKWY, San Jose, CA 95119-1103
- **Phone:** (408) 972-3000
## 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): Permanente Medical Group Inc (NPI 1073606299, Santa Clara, CA); First Choice Physician Partners (NPI 1760724637, Manteca, CA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Stanford University School Of Medicine, class of 2017
## Record status
- **NPPES last updated:** August 1, 2022
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Source: [NPI Profile](https://npiprofile.com/npi/1912438854) · Data from the CMS NPPES public registry.