Dr. Michael Ansstas, MD
- Medicare services, 2024
- 504
- Medicare patients, 2024
- 281
- Part D claims, 2024
- 339
- Hospital affiliations
- 3
- Industry payments
- $5,074
- Practice address
- 1 St Elizabeth Blvd, O'Fallon, IL 62269
- Practice phone
- Call (217) 492-9651
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
HSHS St. Elizabeth's Hospital
O'Fallon, Illinois
Find Dr. Ansstas' professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. Michael Ansstas is a gastroenterologist in O'Fallon, Illinois
Dr. Ansstas practices at HSHS St. Elizabeth's Hospital in O'Fallon, Illinois.
Dr. Ansstas' NPI, 1851658728, was assigned on April 17, 2012. Dr. Ansstas holds Missouri license 2012032351.
- NPI
- 1851658728NPI Registry (opens in a new tab)
- Medicare PAC ID
- 5092084277
- NPI enumeration date
- April 17, 2012
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (217) 492-9651
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 50
- Medical school graduation
- 2002
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Practice Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Michael Ansstas practices at HSHS St. Elizabeth's Hospital in O'Fallon, Illinois
Dr. Ansstas' primary practice is HSHS St. Elizabeth's Hospital, at 1 St Elizabeth Blvd, O'Fallon, IL 62269 in Saint Clair County. The practice phone is (217) 492-9651.
- HSHS St. Elizabeth's Hospital1 St Elizabeth Blvd, O'Fallon, IL 62269 · Saint Clair CountyPhone(217) 492-9651
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Dr. Michael Ansstas is affiliated with 5 sites of care and 3 medical groups
Dr. Ansstas' primary practice is HSHS St. Elizabeth's Hospital in O'Fallon, Illinois. Dr. Ansstas is also affiliated with HSHS St. Elizabeth's Hospital. The medical group on file is HSHS Medical Group. Dmand AI also links Dr. Ansstas to 2 more hospitals, 2 medical groups and 1 group practice or clinic, each named with a free account.
Sources: NPPES NPI Registry (CMS); Dmand AI Practice Data; Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Michael Ansstas' practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Ansstas practices, 4 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| HSHS St. Elizabeth's Hospital | Available with a free account |
| +4 more sites and 2 medical groups | Available with a free account |
Source: Dmand AI Technology Install Data
For health IT teams
Dmand AI maps EHR vendors, IT decision makers and buying committees across each health system and 6.2K+ hospitals, with verified contacts in the same login.
Dr. Michael Ansstas is one of 771 gastroenterologists in Illinois
Gastroenterology is Dr. Ansstas' primary specialty in the NPI Registry, under taxonomy code 207RG0100X. Dmand AI has Dr. Ansstas' licenses on file in 3 states: Missouri, California and Illinois.
Specialties and state licenses
- Gastroenterology, MissouriPrimary
- California license
- Illinois license
Gastroenterologists near Dr. Ansstas
Counts of gastroenterologists with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. Michael Ansstas billed Medicare for 504 services in 2024
CMS data shows 504 Medicare services from Dr. Ansstas across 15 procedure codes in 2024, for 281 Medicare patients. Medicare paid $50,086 for them. Every service was in a facility, such as a hospital, rather than an office.
Dr. Ansstas' Medicare services by type, 2023 to 2024
- 2023
- 2024
- Surgery
- 2023: 962024: 327241%
- Office and hospital visits
- 2023: 1152024: 14627%
- Imaging
- 2023: 02024: 18
- Other services
- 2023: 02024: 13
Dr. Ansstas compared with the Illinois median for gastroenterologists, 2024
- Dr. Ansstas
- Illinois median
- Medicare services
- 504vs 498Close to median
- Medicare patients
- 281vs 3078% below
- Part D claims
- 268vs 37028% below
Medians across 757 gastroenterologists in Illinois with Dmand AI profiles that report each measure.
Dr. Ansstas' most billed Medicare procedure codes, 2024
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
Need commercial claims for Dr. Ansstas?
Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Ansstas and other gastroenterologists in Illinois.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Michael Ansstas treated 281 Medicare patients in 2024, average age 73
CMS counts 281 Medicare patients who saw Dr. Ansstas in 2024. The largest group is 65 to 74, with 120 patients. 75% of them have high blood pressure, and 75% have high cholesterol. 23% are also on Medicaid. Their average risk score is 1.98, where 1.00 is the Medicare average, so they are sicker than most Medicare patients.
Across all payers, Dmand AI patient panel data puts Dr. Ansstas' median patient age at 68, with 55% women.
Dr. Ansstas' Medicare patients by age, 2024
Dr. Ansstas' Medicare patients by sex, 2024
- Women16960%
- Men11240%
Chronic conditions among Dr. Ansstas' Medicare patients, 2024
- High blood pressure75%
- High cholesterol75%
- Arthritis57%
- Chronic kidney disease40%
- Ischemic heart disease39%
- Diabetes38%
- Heart failure37%
- Mood disorders34%
Share of Medicare patients with each condition. A patient can have several.
Dr. Ansstas' patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 68
Patient panel by sex, all payers
- Women55%
- Men44%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Michael Ansstas wrote 339 Medicare Part D claims in 2024
In 2024, Dr. Ansstas wrote 339 Medicare Part D claims for 212 patients. 87% of them were for generic drugs. CMS names the drug for 268 of them, across 4 drugs with 11 or more claims each, at $3,868 in total drug cost. In 2023, CMS named 72 claims across 3 drugs.
Dr. Ansstas' Part D claims by kind of drug, 2024
- Generic295 claims87%
- Brand-name44 claims13%
Dr. Ansstas' most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. Ansstas' Part D claims, 2024
- Antibiotics8%27 of 339 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Part D claims for drugs CMS names, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 722024: 268272%
Drugs named by CMS: 4 in 2024, 3 in 2023.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
Dr. Michael Ansstas ranks in the 97th percentile for upper gastrointestinal (gi) endoscopy for acid reflux in Medicare
Dr. Ansstas accepts Medicare assignment, so Medicare's approved amount is taken as full payment. CMS counts 349 procedures of upper gastrointestinal (gi) endoscopy for acid reflux by Dr. Ansstas, more than 97% of the clinicians it reports for that procedure.
- Accepts Medicare assignment
- Yes
Where Dr. Ansstas ranks in Medicare procedure volume
- Upper gastrointestinal (GI) endoscopy for acid reflux
- 97th percentile349 procedures
- Colonoscopy
- 85th percentile126 procedures
CMS ranks each clinician against every clinician it reports for the same procedure category.
Sources: Doctors and Clinicians National Downloadable File (CMS); and Doctors and Clinicians Utilization Data (CMS)
For MedTech and pharma teams
Filter 7.4M+ HCPs by Medicare procedures, Part D drugs and Open Payments history, then reach them with verified contacts in one login.
Dr. Michael Ansstas received $5,074 in industry payments from 2018 to 2025
CMS Open Payments shows 134 general payments to Dr. Ansstas from 41 drug and device companies from 2018 to 2025. Food and beverage make up the largest share, 55% of the total. Boston Scientific Corporation paid the most, $1,115.
General payments to Dr. Ansstas by program year, 2018 to 2025
General payments to Dr. Ansstas by kind, 2018 to 2025
- Food and beverage$2,80955%
- Travel and lodging$2,26545%
Companies that paid Dr. Ansstas the most, 2018 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Sources for Dr. Michael Ansstas's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice Data |
| Primary practice, affiliations and health system | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice DataDmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab)Doctors and Clinicians Utilization Data (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. Michael Ansstas
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. Michael Ansstas' NPI number?
Dr. Michael Ansstas' NPI number is 1851658728. It was assigned on April 17, 2012, and it is active in the NPI Registry.
What kind of doctor is Dr. Michael Ansstas?
Dr. Michael Ansstas is a gastroenterologist in O'Fallon, Illinois. The primary specialty in the NPI Registry is Gastroenterology Physician (taxonomy code 207RG0100X).
Where does Dr. Michael Ansstas practice?
Dr. Ansstas practices at 1 St Elizabeth Blvd, O'Fallon, IL 62269. Dr. Ansstas' primary practice is HSHS St. Elizabeth's Hospital in O'Fallon, Illinois. Dmand AI also links Dr. Ansstas to 2 hospitals, 2 medical groups and 1 group practice or clinic.
What is Dr. Michael Ansstas' office phone number?
The practice phone on file for Dr. Ansstas is (217) 492-9651.
What is Dr. Michael Ansstas' medical license number?
Dr. Ansstas holds Missouri license 2012032351, one of the licenses on file in 3 states.
Which states has Dr. Michael Ansstas been licensed in?
Dmand AI has state licenses on file for Dr. Ansstas in Missouri, California and Illinois.
Which hospitals is Dr. Michael Ansstas affiliated with?
Dr. Ansstas is affiliated with HSHS St. Elizabeth's Hospital. Dmand AI links Dr. Ansstas to 2 more hospitals.
What medical group is Dr. Michael Ansstas part of?
Dr. Ansstas is linked to HSHS Medical Group. Dmand AI links Dr. Ansstas to 2 more medical groups.
Does Dr. Michael Ansstas accept Medicare?
Yes. CMS data shows Dr. Ansstas billed Medicare for 504 services in 2024, and Dr. Ansstas accepts Medicare assignment.
How many Medicare patients does Dr. Michael Ansstas see?
CMS counts 281 Medicare patients who saw Dr. Ansstas in 2024, with an average age of 73.
Show 4 more questionsShow fewer questions
What services does Dr. Michael Ansstas bill to Medicare?
In 2024, Dr. Ansstas' most billed Medicare services were surgery: digestive system (43239), surgery: digestive system (45385) and hospital inpatient care (99232).
What drugs does Dr. Michael Ansstas prescribe most?
In 2024 Medicare Part D data, Dr. Ansstas' most prescribed drugs by claims were Pantoprazole Sodium, Gavilyte-G and Peg-3350 And Electrolytes.
Has Dr. Michael Ansstas received payments from drug or device companies?
CMS Open Payments shows $5,074 in general payments to Dr. Ansstas from 41 companies from 2018 to 2025. The largest total came from Boston Scientific Corporation.
How long has Dr. Michael Ansstas been practicing?
Dr. Ansstas graduated from medical school in 2002, 24 years ago.
Selling to gastroenterology practices?
See gastroenterologists in Illinois by site of care and group
Find the practices, groups and hospitals they work with, and the right people to contact at each.
- 30 days free
- Self-serve
- No credit card