DR. DIANE C. TSAI M.D.
NPI 1730266966
Radiology - Radiation Oncology in Portland, OR
About Dr. Diane C. Tsai M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. DIANE C. TSAI M.D. (NPI 1730266966) is an individual radiation oncology provider in Portland, Oregon, licensed in Oregon (MD174455) and active in the NPI registry since November 2006. She is enrolled in Medicare PECOS, is affiliated with Providence St Mary Medical Center, and maintains 3 additional practice locations.
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Locations 3
Accepted Insurance
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. Diane C. Tsai 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
14Medicare enrollment records show Diane Tsai reassigns Medicare billing to 14 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Portland, OR 97227
- Reassigned Medicare billing, Oregon and Washington enrollments
- Also billed through NPI 1184786527 (Washington)
- 3,207 clinicians in this Medicare group
Portland, OR 97216
- Reassigned Medicare billing, Oregon enrollment
- 137 clinicians in this Medicare group
Portland, OR 97216
- Reassigned Medicare billing, Oregon enrollment
- 331 clinicians in this Medicare group
Springfield, OR 97477
- Reassigned Medicare billing, Oregon enrollment
- 30 clinicians in this Medicare group
Tacoma, WA 98405
- Reassigned Medicare billing, Washington enrollment
- 10 clinicians in this Medicare group
Gig Harbor, WA 98332
- Reassigned Medicare billing, Washington enrollment
- 11 clinicians in this Medicare group
Coos Bay, OR 97420
- Reassigned Medicare billing, Oregon enrollment
- 327 clinicians in this Medicare group
Sedro Woolley, WA 98284
- Reassigned Medicare billing, Washington enrollment
- Also billed through NPI 1548698806 (Washington)
- 76 clinicians in this Medicare group
College Place, WA 99324
- Reassigned Medicare billing, Washington enrollment
- 276 clinicians in this Medicare group
Bellingham, WA 98225
- Reassigned Medicare billing, Washington enrollment
- 390 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 6
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.
Hospital Affiliations CMS Care Compare
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Providence St Mary Medical Center
Acute Care Hospitals · Walla Walla, WAPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 97227 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 8
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
PORTLAND, OR 97227
PORTLAND, OR 97227
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 Diane Tsai's NPI number?
The NPI number for Diane Tsai is 1730266966. It was assigned to this individual provider in the NPPES registry on November 1, 2006.
Where is Diane Tsai located?
Diane Tsai practices at 3620 N Interstate Ave, Portland, OR 97227. The listed phone number is (503) 813-2000.
What is Diane Tsai's specialty?
The primary specialty registered for this NPI is Radiology, specializing in Radiation Oncology, with taxonomy code 2085R0001X.
Is Diane Tsai enrolled in Medicare?
Yes. Diane Tsai 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 Diane Tsai's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Diane Tsai reassigns Medicare benefits to 14 organizations: Kaiser Foundation Health Plan Of The Northwest (Portland, OR), Portland Adventist Medical Center (Portland, OR), Portland Adventist Medical Center (Portland, OR), Oregon Urology Institute PC (Springfield, OR), Tacoma Radiation Oncology Center Inc, Ps (Tacoma, WA) and 9 more organizations, 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 Diane Tsai's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Diane Tsai accept?
Health plans from Ambetter Health, BridgeSpan Health Company, Moda Health Plan, Inc., Premera Blue Cross Blue Shield of Alaska and Providence Health Plan and 1 other insurer list Diane Tsai as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
Is Diane Tsai affiliated with any hospitals?
According to CMS data, Diane Tsai is affiliated with Providence St Mary Medical Center.
When was this NPI record last updated?
The NPPES record for Diane Tsai was last updated on December 9, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 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. Diane C. Tsai, M.D. · NPI 1730266966
Radiation Oncology physician in Portland, Oregon. Individual provider, active in the CMS NPPES registry since November 1, 2006.
## Identity
- **NPI:** 1730266966 (Entity type: Individual)
- **Enumerated:** November 1, 2006
- **Primary specialty:** Radiology - Radiation Oncology · taxonomy 2085R0001X
- **State license:** MD174455 (Oregon)
- **Sole proprietor:** No
## Practice location
- **Address:** 3620 N INTERSTATE AVE, Portland, OR 97227-1106
- **Phone:** (503) 813-2000
## 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:** 14 organizations under Medicare reassignment (form CMS-855R): Kaiser Foundation Health Plan Of The Northwest (NPI 1093043424, Portland, OR); Portland Adventist Medical Center (NPI 1215910302, Portland, OR); Portland Adventist Medical Center (NPI 1750091021, Portland, OR); Oregon Urology Institute PC (NPI 1801812078, Springfield, OR); Tacoma Radiation Oncology Center Inc, Ps (NPI 1255449146, Tacoma, WA); and 9 more · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 1991
## Record status
- **NPPES last updated:** December 9, 2025
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Source: [NPI Profile](https://npiprofile.com/npi/1730266966) · Data from the CMS NPPES public registry.