RITCHIE ALLEN LARSON M.D.
NPI 1235280462
Anesthesiology in Seattle, WA
About Ritchie Allen Larson M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
RITCHIE ALLEN LARSON M.D. (NPI 1235280462) is an individual anesthesiology provider in Seattle, Washington, licensed in Washington (MD00032132) and active in the NPI registry since January 2007. He is enrolled in Medicare PECOS.
NPPES Registry Identity
Specialties & Licenses
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 (PECOS)
Ritchie Allen Larson M.d. is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Medicare Billing Reassignment
Medicare enrollment records show Ritchie Larson reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Seattle, WA 98122
- Reassigned Medicare billing, Washington enrollment
- 233 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.
SEATTLE, WA 98104
SEATTLE, WA 98104
SEATTLE, WA 98104
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 Ritchie Larson's NPI number?
The NPI number for Ritchie Larson is 1235280462. It was assigned to this individual provider in the NPPES registry on January 15, 2007.
Where is Ritchie Larson located?
Ritchie Larson practices at 1229 Madison St Suite 1440, Seattle, WA 98104. The listed phone number is (206) 625-0578.
What is Ritchie Larson's specialty?
The primary specialty registered for this NPI is Anesthesiology with taxonomy code 207L00000X.
Is Ritchie Larson enrolled in Medicare?
Yes. Ritchie Larson is registered in the Medicare PECOS enrollment system.
Which organization bills Medicare for Ritchie Larson's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Ritchie Larson reassigns Medicare benefits to Physicians Anesthesia Service PLLC (Seattle, WA). The 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 Ritchie Larson'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 Ritchie Larson was last updated on April 14, 2008. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 18 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.
# Ritchie Allen Larson, M.D. · NPI 1235280462
Anesthesiology physician in Seattle, Washington. Individual provider, active in the CMS NPPES registry since January 15, 2007.
## Identity
- **NPI:** 1235280462 (Entity type: Individual)
- **Enumerated:** January 15, 2007
- **Primary specialty:** Anesthesiology · taxonomy 207L00000X
- **State license:** MD00032132 (Washington)
- **Sole proprietor:** No
## Practice location
- **Address:** 1229 MADISON ST, SUITE 1440, Seattle, WA 98104-3586
- **Phone:** (206) 625-0578 · **Fax:** (206) 625-9184
## 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:** Physicians Anesthesia Service PLLC (NPI 1417962200, Seattle, WA), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
## Record status
- **NPPES last updated:** April 14, 2008
- **Other identifiers:** Medicare UPIN G48530; Medicare PIN GAB10950; Medicaid 8241085 (WA)
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Source: [NPI Profile](https://npiprofile.com/npi/1235280462) · Data from the CMS NPPES public registry.