Stephen Walston, MD
NPI 1578887519 · Internal Medicine Physician · Mercer Island, WA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Stephen Walston, MD is a Internal Medicine Physician provider in Mercer Island, WA (NPI 1578887519).
Provider details
- NPI number
- 1578887519
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- MD60423761 (WA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
16 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
750 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 283 | $140 |
| Visit Complexity Inherent to Evaluation and Management Associated With Medical Care Services That Serve As the Continuing Focal Point for All Needed Health Care Services And/Or With Medical Care Services That Are Part of Ongoing Care Related to a Patient'SG2211 | 228 | $17 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 79 | $143 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 48 | $99 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 19 | $182 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 55 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 275 | 91 |
| Amlodipine Besylate | 138 | 46 |
| Levothyroxine Sodium | 119 | 31 |
| Lisinopril | 115 | 30 |
| Losartan Potassium | 114 | 33 |
| Tamsulosin Hcl | 71 | 27 |
| Rosuvastatin Calcium |
Practice location
Mailing address
Registry dates
- Enumerated
- 2010-03-19
- Last updated
- 2021-11-11
- Certified
- 2021-11-11
Frequently asked questions
- What is Stephen Walston's NPI number?
- Stephen Walston's National Provider Identifier (NPI) is 1578887519, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Stephen Walston's specialty?
- Stephen Walston is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Stephen Walston located?
- Stephen Walston's practice location on file with NPPES is 3236 78th Ave Se Ste 200, Mercer Island, WA 98040-3500.
- What is Stephen Walston's phone number?
- The practice phone number listed in the NPPES registry for Stephen Walston is (206) 386-9500.
- Does Stephen Walston accept Medicare?
- Stephen Walston is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Stephen Walston's NPI active?
- Yes — Stephen Walston's NPI (1578887519) is active in the NPPES registry as of the last update on 2021-11-11.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.