Stephen Louis Walston, MD
Internal Medicine Physician · Mercer Island, WA
Stephen Louis Walston, MD is an internal medicine physician with a practice address in Mercer Island, Washington, and NPI 1578887519, issued on Mar 19, 2010. Check the license (Washington MD60423761, as entered in NPPES) on the Washington Medical Commission; the Medicare figures below come from public CMS files.
- Name
- Stephen Louis Walston
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- MD60423761 WA
Self-reported in NPPES; status is on the state search - Practice location
- 3236 78TH Ave SE Ste 200, Mercer Island, WA 98040
- Phone
- (206) 386-9500
- Enumerated
- Mar 19, 2010
- Record last updated
- Nov 11, 2021 (not updated in 5 years: call before relying on the address or phone)
- Fax
- (206) 386-9605
- Medicaid IDs
- 1578887519 WA
2022131 WA - Medicare enrollment
- Enrolled (PECOS I20140213000002); accepts Medicare assignment
- Medical or professional school
- University Of Texas Medical School At Houston, 2010
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 3,079 in Washington → Look up another NPI →
Also registered at 3236 78TH Ave SE Ste 200
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Stephen Louis Walston in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWashington Medical Commission
Search for license MD60423761Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
11% fewer Medicare Part D claims than the average internal medicine physician in 2024
2,839 Medicare Part D claims for 274 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. 26 claims were for opioids.
Most prescribed
- Atorvastatin Calcium275 claims
- Amlodipine Besylate138 claims
- Levothyroxine Sodium119 claims
- Lisinopril115 claims
- Losartan Potassium114 claims
- Rosuvastatin Calcium71 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Bills Medicare through 3 group practices
- Select Outpatient Services IncGlenview, IL
- Select Rehabilitation, LLCGlenview, IL
- Swedish Health ServicesMercer Island, WA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Stephen Louis Walston among 3,079 internal medicine physician records in Washington
Stephen Louis Walston, MD is one of 3,079 internal medicine physician records with a practice address in Washington. 75% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2010, is newer than 62% of them.
- NPI issued2010 · 62% of these records are older, 35% newer
- In a Medicare fileYes · 75% of these records are
- In the CMS Doctors and Clinicians fileYes · 60% of these records are
- Graduated2010 · median 2006 among the 1,852 with a school on file
- Record last updated2021 · 63% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a Washington practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
13 internal medicine physician records list a practice address in Mercer Island
They are 13 of the 331 NPPES records with a practice address in Mercer Island, and 3,079 internal medicine physician records in Washington.
All 3,079 in Washington → Every provider in Mercer Island → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Steven Dunning, MDMercer Island, WA 980401083941405
- Martin Gelfand, M.D.Mercer Island, WA 980401609299841
- Rutherford Hayes, MDMercer Island, WA 980401811072614
- Daniel Kent, M.D.Mercer Island, WA 980401184743809
- Keith Luther, MDMercer Island, WA 980401912001652
- James Martin, MDMercer Island, WA 980401881681369
- Linda Rosenstock, MDMercer Island, WA 980401275803157
- Leonard Rosoff, M.D.Mercer Island, WA 980401730533001
Common questions
What is Stephen Louis Walston, MD's NPI number?
Stephen Louis Walston, MD's National Provider Identifier (NPI) is 1578887519, issued on Mar 19, 2010. An NPI identifies a provider in billing; it is not a license.
Where is Stephen Louis Walston, MD located?
The NPPES record lists a practice address at 3236 78TH Ave SE Ste 200, Mercer Island, WA, 98040. Phone: (206) 386-9500. Providers update this record themselves, so call before visiting.
How can I verify Stephen Louis Walston, MD's license?
NPPES lists Washington license number MD60423761, as entered by the provider. Search the Washington Medical Commission at https://wahelms.my.site.com/s/license-search. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Stephen Louis Walston, MD prescribe under Medicare Part D?
In 2024, Stephen Louis Walston, MD had 2,839 Medicare Part D claims for 274 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.