Doctor profile · Federal record

Dr. Stephen Walston, MD

Internal Medicine Physician (CMS: Internal Medicine) · Mercer Island, WA

  • NPI 1578887519
  • Accepts Medicare
  • 16 yrs in practice
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
3236 78Th Ave Se Ste 200
Mercer Island, WA 980403500
(206) 386-9500
fax (206) 386-9605
Mailing address
Po Box 25608
Salt Lake City, UT 841250608

Credentials & registration

NPPES · NUCC
NPI registered
March 2010 — 16 yrs on file
Profile last updated
November 11, 2021
Year of graduation
2010 — 16 yrs since
Specialty taxonomy
207R00000X — NUCC code
State license (1)
Washington #MD60423761
Medicaid (2)
WA #1578887519 · WA #2022131

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1578887519. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
481
Distinct HCPCS
9
Medicare allowed
$64,682
HCPCS Description Services Patients Avg allowed
99214 Established patient office or other outpatient visit, 30-39 minutes 240 137 $138
G0439 Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit 63 63 $142
99213 Established patient office or other outpatient visit, 20-29 minutes 59 51 $97
99204 New patient office or other outpatient visit, 45-59 minutes 43 43 $182
99215 Established patient office or other outpatient visit, 40-54 minutes 26 18 $196
93005 Routine electrocardiogram (ecg) using at least 12 leads with tracing 16 16 $8
G0009 Administration of pneumococcal vaccine 12 12 $34
90677 Pneumococcal conjugate vaccine, 20 valent (pcv20), for intramuscular use 11 11 $282
G0008 Administration of influenza virus vaccine 11 11 $34

In context: peer comparison

Among 4 peers in Mercer Island Internal Medicine Physician, average services per provider: 76. This provider delivers 6.3× the peer median.

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
979
Patients
299
Total drug cost
$110,196
Drug Type Claims Patients Total cost
Atorvastatin Calcium Generic 196 66 $2,703
Amlodipine Besylate Generic 126 43 $977
Levothyroxine Sodium Generic 92 32 $1,181
Losartan Potassium Generic 89 28 $1,175
Rosuvastatin Calcium Generic 71 24 $2,398
Lisinopril Generic 60 21 $611
Eliquis (Apixaban) Brand 56 12 $60,934
Tamsulosin Hcl Generic 52 17 $1,570
Metoprolol Succinate Generic 48 20 $1,104
Metformin Hcl Generic 36 13 $320

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. Stephen Walston's medical specialty?
Dr. Stephen Walston practices Internal Medicine Physician in Mercer Island, WA.
Where does Dr. Stephen Walston practice?
Dr. Stephen Walston practices at 3236 78Th Ave Se Ste 200, Mercer Island, WA 980403500. Office phone: 2063869500.
What is Dr. Stephen Walston's NPI?
Dr. Stephen Walston's National Provider Identifier (NPI) is 1578887519, issued by NPPES.
Does Dr. Stephen Walston accept Medicare assignment?
Yes. Dr. Stephen Walston accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Stephen Walston commonly perform?
Top Medicare-reported procedures in 2023: Established patient office or other outpatient visit (HCPCS 99214); Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit (HCPCS G0439); Established patient office or other outpatient visit (HCPCS 99213). Source: CMS Medicare Physician & Other Practitioners file.