WILLIAM MESSER M.D. PH.D.
NPI 1508085739
Internal Medicine - Infectious Disease in Portland, OR
About William Messer M.d. Ph.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
WILLIAM MESSER M.D. PH.D. (NPI 1508085739) is an individual infectious disease provider in Portland, Oregon, licensed in Oregon (MD160501) and active in the NPI registry since April 2007. He is enrolled in Medicare PECOS, is affiliated with Ohsu Hospital And Clinics, and is a graduate of University Of North Carolina At Chapel Hill School Of Medicine (2006).
NPPES Registry Identity
Specialties & Licenses
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 Messer M.d. Ph.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
3Medicare enrollment records show William Messer reassigns Medicare billing to 3 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Portland, OR 97239
- Reassigned Medicare billing, Oregon enrollment
- 2,212 clinicians in this Medicare group
Hillsboro, OR 97123
- Reassigned Medicare billing, Oregon enrollment
- 691 clinicians in this Medicare group
Hillsboro, OR 97123
- Reassigned Medicare billing, Oregon enrollment
- 185 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 2
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 2
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Ohsu Hospital And Clinics
Acute Care Hospitals · Portland, ORHillsboro Medical Center
Acute Care Hospitals · Hillsboro, ORPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 97239 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
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.
PORTLAND, OR 97239
PORTLAND, OR 97239
PORTLAND, OR 97239
PORTLAND, OR 97239
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 Messer's NPI number?
The NPI number for William Messer is 1508085739. It was assigned to this individual provider in the NPPES registry on April 25, 2007.
Where is William Messer located?
William Messer practices at 3181 SW Sam Jackson Park Rd L457, Portland, OR 97239. The listed phone number is (503) 494-7735.
What is William Messer's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Infectious Disease, with taxonomy code 207RI0200X.
Is William Messer enrolled in Medicare?
Yes. William Messer 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 Messer's services?
According to the CMS Revalidation Reassignment List (October 2026 release), William Messer reassigns Medicare benefits to 3 organizations: University Professional Services (Portland, OR), Tuality Medical Group LLC (Hillsboro, OR) and Tuality Healthcare (Hillsboro, OR). 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 Messer's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does William Messer accept?
Health plans from Moda Health Plan, Inc. and PacificSource Health Plans list William Messer 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 Messer affiliated with any hospitals?
According to CMS data, William Messer is affiliated with Ohsu Hospital And Clinics and Hillsboro Medical Center.
When was this NPI record last updated?
The NPPES record for William Messer was last updated on November 6, 2012. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 13 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 Messer, M.D. PH.D. · NPI 1508085739
Infectious Disease physician in Portland, Oregon. Individual provider, active in the CMS NPPES registry since April 25, 2007.
## Identity
- **NPI:** 1508085739 (Entity type: Individual)
- **Enumerated:** April 25, 2007
- **Primary specialty:** Internal Medicine - Infectious Disease · taxonomy 207RI0200X
- **State license:** MD160501 (Oregon)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 3181 SW SAM JACKSON PARK RD, L457, Portland, OR 97239-3011
- **Phone:** (503) 494-7735
## 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:** 3 organizations under Medicare reassignment (form CMS-855R): University Professional Services (NPI 1376709535, Portland, OR); Tuality Medical Group LLC (NPI 1639690704, Hillsboro, OR); Tuality Healthcare (NPI 1073817714, Hillsboro, OR) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** University Of North Carolina At Chapel Hill School Of Medicine, class of 2006
## Record status
- **NPPES last updated:** November 6, 2012
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Source: [NPI Profile](https://npiprofile.com/npi/1508085739) · Data from the CMS NPPES public registry.