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Internal Medicine Providers in O Fallon, MO

Browse 17 Internal Medicine providers listed in NPPES with a practice address in O Fallon, Missouri.

17 Healthcare Providers

How O Fallon compares with the U.S.

O Fallon has 18 clinicians in Internal Medicine per 100,000 residents, about 41% of the U.S. rate of 44.

That is 17 active clinicians in Internal Medicine with a practice address in O Fallon, for a population of 93,801.

The Missouri rate is 42 per 100,000 residents.

What these numbers mean

Clinicians per 100,000 residents compares places of different sizes. We count active clinicians who list a practice address in the area in the federal NPI registry (NPPES) and divide by the number of people who live there, according to the U.S. Census Bureau. The U.S. rate is the same calculation for the whole country.

A higher number does not mean it is easier to get an appointment, that wait times are shorter, or that care is better. It also does not show how many clinicians are accepting new patients or which insurance plans they take. A lower number does not by itself mean there is a shortage.

City counts use the city name in each clinician's practice address. That postal city can cover a larger or smaller area than the city limits the Census Bureau uses for population, and many clinicians list only one address even if they work in several places.

93% of clinicians in Internal Medicine in O Fallon listed in the CMS Medicare file (13 of 14) accept Medicare assignment. That is similar to the Missouri share of 97%.

What is Medicare assignment?

A clinician who accepts Medicare assignment agrees to take the Medicare-approved amount as full payment for services that Original Medicare covers. You usually still pay your deductible and coinsurance. This comes from the CMS Doctors and Clinicians file and applies to Original Medicare only. Medicare Advantage plans have their own provider networks. It does not show whether a clinician is taking new patients.

Some clinicians are listed as "may accept assignment," which means they can decide case by case. Clinicians without an assignment flag, or who are not in the CMS file, are not counted as accepting assignment. That does not mean they refuse Medicare. Ask the office before your visit.

43% of clinicians in Internal Medicine in O Fallon listed in the CMS Medicare file (6 of 14) have a CMS telehealth indicator, meaning their recent Medicare claims include telehealth services. That is higher than the Missouri share of 21%.

About the telehealth indicator

The telehealth indicator comes from CMS. It marks clinicians whose recent paid Medicare claims include services delivered by telehealth. It means a clinician has provided some services by telehealth, not that every visit can be done online. A clinician without the indicator may still offer telehealth, for example to patients who are not on Medicare. Ask the office which visits can be done by video or phone.

These figures summarize public federal data. They do not measure quality of care, appointment availability, or whether a clinician accepts your insurance or new patients. Registry addresses can be out of date. Please confirm details directly with the office and your plan. This information is not medical advice.

Prepared by T-MedInfo from NPPES, CMS and U.S. Census Bureau data. Questions or corrections: support@true-medinfo.com ยท Methodology

Sources: Clinician counts and practice addresses: NPPES NPI Registry, Centers for Medicare & Medicaid Services (CMS), data as of August 2026. Medicare assignment and telehealth indicators: CMS Doctors and Clinicians National Downloadable File. Population: U.S. Census Bureau, American Community Survey 2020-2024 5-Year Estimates, Table B01003 (Total Population).

Internal Medicine Medicare (PECOS) Enrollment & Ordering Eligibility

Medicare enrollment and order/referring eligibility listed by CMS for Internal Medicine practitioners in O Fallon, MO

Source: CMS PECOS
PECOS Enrolled Specialists 14 In O Fallon, MO
Part B Lab & Imaging Eligible 15 Diagnostic Referrals
DME Ordering Eligible 15 Durable Medical Equipment
Home Health Agency Referrals 15 HHA Ordering Eligible
Showing 1โ€“17 of 17 providers
With recent CMS data first, then Aโ€“Z

Dr. Daniela Blum Morales , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
2223 Technology Dr Ste 40, O Fallon, MO 633687272
Phone: 6367554400
NPI Identifier 1730561069
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Active NPI Status Accepts Medicare Assignment Telehealth Services Available
300 Winding Woods Dr Ste 214, O Fallon, MO 633664773
Phone: 6366143289
NPI Identifier 1417307505
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Dr. Amy Kathleen Davis , MD

Internal Medicine

Active NPI Status
1008 Rock Creek Elementary School Dr, O Fallon, MO 633667576
Phone: 6362814410
NPI Identifier 1245453844
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Dr. Gregory P Genova , MD

Internal Medicine

Active NPI Status
5551 Winghaven Blvd Ste 250, O Fallon, MO 633683630
Phone: 6366857724
NPI Identifier 1750377941
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Dr. Naman A Ghazal-Albar , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
5551 Winghaven Blvd, Suite 260, O Fallon, MO 633683617
Phone: 6362003811
NPI Identifier 1639144785
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Dr. Gary D Gray , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
5551 Winghaven Blvd, Ste 290, O Fallon, MO 633683617
Phone: 6366952575
NPI Identifier 1497729826
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Dr. Brian A Grus , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
20 Progress Point Pkwy Ste 108, O Fallon, MO 633682207
Phone: 6363442400
NPI Identifier 1053421065
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Matthew Meier

Internal Medicine

Active NPI Status Accepts Medicare Assignment
1002 Peruque Crossing Ct, Suite 102, O Fallon, MO 633662362
Phone: 6362945757
NPI Identifier 1578574372
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Dr. Jyotirmaya Nanda , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
1101 Highway K, O Fallon, MO 633668431
Phone: 6363798138
NPI Identifier 1629039714
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Dr. Geraldine A. Ryan , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
9426 Phoenix Village Pkwy, O Fallon, MO 633684781
Phone: 6365615999
NPI Identifier 1689640609
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Dr. Rajiv Sadana , MD

Internal Medicine

Active NPI Status
844 Waterbury Falls Drive, St Charles Cboc, O'fallon, MO 63368
Phone: 3142897676
NPI Identifier 1669423034
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Dr. Aaron Robert Steimel , DO

Internal Medicine

Active NPI Status
20 Progress Point Pkwy Ste 108, O Fallon, MO 633682207
Phone: 6363442400
NPI Identifier 1659067874
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Dr. Alan William Steube , DO

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
2223 Technology Dr Ste 40, O Fallon, MO 633687272
Phone: 6367554400
NPI Identifier 1740857457
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Dr. Jamie Lee Tueth , DO

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
20 Progress Point Pkwy, Ste 108, O Fallon, MO 633682206
Phone: 6363442400
NPI Identifier 1619100989
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Dr. Kevin D Weikart , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
1002 Peruque Crossing Ct, Suite 101, O Fallon, MO 633662362
Phone: 6362945900
NPI Identifier 1902864986
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Kevin Tianber Yin

Internal Medicine

Active NPI Status Accepts Medicare Assignment
2223 Technology Dr Ste 35, O Fallon, MO 633687272
Phone: 6365615999
NPI Identifier 1689311011
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Dr. Nadia Zia , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
2 Progress Point Ct, O Fallon, MO 633682208
Phone: 3143170600
NPI Identifier 1134164825
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Frequently Asked Questions about Internal Medicine in O Fallon

How do I check a Internal Medicine practitioner's license?

Each practitioner profile shows the NUCC taxonomy code and any state license number the practitioner reported to NPPES, plus a link to the Missouri licensing board lookup. NPPES entries are self-reported; current license status is published only by the state board.

Why is a practitioner missing from this list?

This list shows NPI records that are active in NPPES. A deactivated NPI keeps its profile with the deactivation date and practice history; find it with the site search by name or NPI number.