Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

Dr. Michael Ansstas, MD

Individual provider Gastroenterology Physician · NPI 1851658728

Dr. Michael Ansstas, MD practises Gastroenterology in Saint Louis, Missouri. Qualified in 2002, 24 years ago. Practices with Archbold Medical Group, Inc, a 81-clinician group, works from 3 locations and accepts Medicare assignment. Licensed in California, Illinois and Missouri.

Years since qualifying
24
Licensed in
CA, IL, MO
In the registry since
2012
Specialties on file
3
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

See every abbreviation used in this directory →

Claim this listing Report a problem Suggest an edit

Practice location Address checks out

11155 Dunn Rd Ste 309E
Saint Louis, MO 63136-6111
Phone: (314) 953-8799
Show map & directions

Directions in Google Maps · Apple Maps · OpenStreetMap

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (2)

  • 4 Memorial Dr Ste 230b, Alton, IL 62002-6705 — (618) 463-7874
  • 3 Saint Elizabeth Blvd, O Fallon, IL 62269-1281 — (618) 641-5803

Specialties & licences

Gastroenterology Physician (primary) Taxonomy 207RG0100X · Licence 2012032351 (MO)
Gastroenterology Physician Taxonomy 207RG0100X · Licence 036153515 (IL)
Gastroenterology Physician Taxonomy 207RG0100X · Licence A160085 (CA)

Record details

NPI number1851658728
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedApril 17, 2012
Last updated in NPPESOctober 27, 2025
Certification dateOctober 27, 2025

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyGASTROENTEROLOGY
Also practisesALLERGY/IMMUNOLOGY, INTERNAL MEDICINE
Medical schoolOTHER
Graduated 2002 (24 years in practice)
Group practice Archbold Medical Group, Inc. — 81 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 on file with Medicare

Procedures

From CMS Care Compare, which counts the procedures a clinician billed to Original Medicare and Medicare Advantage over a recent 12-month period. CMS reports a fixed list of common procedures, so this is not everything the clinician does. Counts of 10 or fewer are given as a range, because CMS withholds small numbers.

Upper gastrointestinal (GI) endoscopy for acid reflux 297 times · 95th percentile
Colonoscopy 114 times · 83rd percentile

The percentile compares how often this clinician performed the procedure with other clinicians who performed it, as CMS calculates it. It measures volume, not outcomes or skill.

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients281
Services billed 626 a service is one billed item, such as a visit, a test or a procedure
Average patient age73

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $104 1 payment · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician. Those with a page here are linked.

Colleagues at Archbold Medical Group, Inc

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 81 clinicians in the practice; 12 are shown here.

Other providers in Saint Louis