WILLIAM D LACK M.D.
NPI 1922204635
Orthopaedic Surgery - Orthopaedic Trauma in Seattle, WA
About William D Lack M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
WILLIAM D LACK M.D. (NPI 1922204635) is an individual orthopaedic trauma provider in Seattle, Washington, licensed in Washington (MD60872422) and active in the NPI registry since June 2007. He is enrolled in Medicare PECOS, is affiliated with University Of Washington Medical Ctr, and is a graduate of Harvard Medical School (2007).
NPPES Registry Identity
Specialties & Licenses 2
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
William D Lack 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 Reassignment
Medicare enrollment records show William Lack reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Seattle, WA 98104
- Reassigned Medicare billing, Washington enrollment
- 4,364 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.
Hospital Affiliations CMS Care Compare
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
University Of Washington Medical Ctr
Acute Care Hospitals · Seattle, WAOther Providers at the Same Location NPPES 7
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
SEATTLE, WA 98133
SEATTLE, WA 98133
SEATTLE, WA 98133
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 Lack's NPI number?
The NPI number for William Lack is 1922204635. It was assigned to this individual provider in the NPPES registry on June 21, 2007.
Where is William Lack located?
William Lack practices at 11011 Meridian Ave N Ste 201, Seattle, WA 98133. The listed phone number is (206) 520-5000.
What is William Lack's specialty?
The primary specialty registered for this NPI is Orthopaedic Surgery, specializing in Orthopaedic Trauma, with taxonomy code 207XX0801X.
Is William Lack enrolled in Medicare?
Yes. William Lack 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 organization bills Medicare for William Lack's services?
According to the CMS Revalidation Reassignment List (October 2026 release), William Lack reassigns Medicare benefits to The Association Of University Physicians (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 William Lack's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does William Lack accept?
Health plans from Premera Blue Cross Blue Shield of Alaska and Providence Health Plan list William Lack 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 William Lack affiliated with any hospitals?
According to CMS data, William Lack is affiliated with University Of Washington Medical Ctr.
When was this NPI record last updated?
The NPPES record for William Lack was last updated on August 9, 2018. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 8 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 D Lack, M.D. · NPI 1922204635
Orthopaedic Trauma physician in Seattle, Washington. Individual provider, active in the CMS NPPES registry since June 21, 2007.
## Identity
- **NPI:** 1922204635 (Entity type: Individual)
- **Enumerated:** June 21, 2007
- **Primary specialty:** Orthopaedic Surgery - Orthopaedic Trauma · taxonomy 207XX0801X
- **State license:** MD60872422 (Washington)
- **Sole proprietor:** No
## Practice location
- **Address:** 11011 MERIDIAN AVE N STE 201, Seattle, WA 98133
- **Phone:** (206) 520-5000
## 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:** The Association Of University Physicians (NPI 1023041159, Seattle, WA), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Harvard Medical School, class of 2007
## Record status
- **NPPES last updated:** August 9, 2018
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Source: [NPI Profile](https://npiprofile.com/npi/1922204635) · Data from the CMS NPPES public registry.