Doctor profile · Federal record

Dr. Benjamin Siemanowski, M.D.

Gastroenterology Physician (CMS: Gastroenterology) · Bellingham, WA

  • NPI 1548301120
  • Accepts Medicare
  • MIPS 87.2 / 100 · 2023
  • 26 yrs in practice
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
3111 Woburn St Ste 201
Bellingham, WA 982266610
(360) 734-1420
fax (360) 733-1659

Credentials & registration

NPPES · NUCC
NPI registered
February 2007 — 19 yrs on file
Profile last updated
May 24, 2023
Year of graduation
2000 — 26 yrs since
Specialty taxonomy
207RG0100X — NUCC code
State license (1)
Washington #MD00047499
Medicaid
WA #1548301120

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1548301120. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
1,034
Distinct HCPCS
10
Medicare allowed
$107,718
HCPCS Description Services Patients Avg allowed
88305 Pathology examination of tissue using a microscope, intermediate complexity 414 222 $36
45385 Removal of polyps or growths of large bowel using an endoscope with mechanical snare 184 183 $249
99214 Established patient office or other outpatient visit, 30-39 minutes 131 105 $128
43239 Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope 61 59 $96
G0500 Moderate sedation services provided by the same physician or other qualified health care professional performing a gastrointestinal endoscopic service that sedation supports, requiring the presence of an independent trained observer to assist in the monito 56 56 $5
45380 Biopsy of large bowel using a flexible endoscope 35 34 $105
G0105 Colorectal cancer screening; colonoscopy on individual at high risk 26 26 $178
99204 New patient office or other outpatient visit, 45-59 minutes 25 25 $168
43235 Diagnostic exam of esophagus, stomach, and/or upper small bowel using a flexible endoscope 23 23 $98
43248 Insertion of guide wire with dilation of esophagus using a flexible endoscope 18 18 $142

In context: peer comparison

Among 10 peers in this city , average services per provider: 60. This provider delivers 17× the peer median.

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
883
Patients
408
Total drug cost
$411,259
Drug Type Claims Patients Total cost
Omeprazole Generic 276 76 $4,079
Sod Sulf-Potass Sulf-Mag Sulf (Sodium, Potassium,mag Sulfates) Brand 197 195 $15,054
Pantoprazole Sodium Generic 74 19 $1,690
Peg 3350-Electrolyte (Sodium Chloride/Nahco3/Kcl/Peg) Brand 72 70 $2,009
Mesalamine Generic 61 0 $59,628
Azathioprine Generic 34 0 $1,841
Humira(Cf) Pen (Adalimumab) Brand 31 0 $317,673
Lansoprazole Generic 27 0 $1,174
Famotidine Generic 20 0 $271
Plenvu (Peg3350/Sod Sul/Nacl/Kcl/Asb/C) Brand 19 19 $2,760

Frequently asked questions

Auto-generated from federal data
What is Dr. Benjamin Siemanowski's medical specialty?
Dr. Benjamin Siemanowski practices Gastroenterology Physician in Bellingham, WA.
Where does Dr. Benjamin Siemanowski practice?
Dr. Benjamin Siemanowski practices at 3111 Woburn St Ste 201, Bellingham, WA 982266610. Office phone: 3607341420.
What is Dr. Benjamin Siemanowski's NPI?
Dr. Benjamin Siemanowski's National Provider Identifier (NPI) is 1548301120, issued by NPPES.
Does Dr. Benjamin Siemanowski accept Medicare assignment?
Yes. Dr. Benjamin Siemanowski accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Benjamin Siemanowski commonly perform?
Top Medicare-reported procedures in 2023: Pathology examination of tissue using a microscope, intermediate complexity (HCPCS 88305); Removal of polyps or growths of large bowel using an endoscope with mechanical snare (HCPCS 45385); Established patient office or other outpatient visit (HCPCS 99214). Source: CMS Medicare Physician & Other Practitioners file.