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Dr. Nathan Philip Seigrist , DO

General Practice β€’ O Fallon, IL

Active NPI 1780382465 Individual Practitioner Male Practitioner
Practice location in NPPES

3 Saint Elizabeth Blvd Ste 4000
O Fallon, IL 622691284

Call 6182569355 Location details and other listings
Medical Disclaimer

This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.

Practice Location & Contact Primary Location

Practice Address

3 Saint Elizabeth Blvd Ste 4000

O Fallon, IL 622691284

Telephone 6182569355
Fax 6182062332
Organization at the Same NPPES Address or Phone
Southern Illinois Healthcare Foundation Inc Facility NPI 1225556996

Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.

Industry payments (Open Payments)

Fewer than 11 payment records totaling $31.94 in 2025

Drug and medical device companies must report certain payments to doctors and some other clinicians to CMS, such as meals, travel, speaking fees or research funding.

These records are submitted by drug and medical device companies, and a reported payment does not necessarily mean the financial relationship is improper.

General: payments not tied to research, such as meals, travel, consulting or speaking fees.

A reported payment does not necessarily mean the financial relationship is improper. Research payments can go to a hospital or university for a study the clinician leads, not to the clinician personally. Clinicians can dispute records with the company that reported them.

Source: CMS Open Payments, program year 2025.

Guide: How to read an Open Payments record

NPI first issued

2023

The year this clinician's National Provider Identifier (NPI) was issued. An NPI is a unique 10-digit ID that US health care providers use for billing.

What this does not show: NPI first issued

NPIs have been issued only since 2005, so this year is not necessarily when the clinician started practicing.

Source: CMS NPPES NPI Registry.

Medicare assignment not listed

CMS data do not show whether this clinician accepts Medicare assignment. This does not mean they do not accept Medicare. Ask the office.

Medicare assignment applies to Original Medicare. It does not tell you whether the clinician is in a Medicare Advantage plan's network, accepts other insurance, or is taking new patients.

Source: CMS Doctors and Clinicians; Medicare.gov, β€œDoes your provider accept Medicare as full payment?”

Guide: What Medicare assignment means

No telehealth indicator

CMS shows this indicator only when recent Medicare claims include telehealth services. The clinician may still offer telehealth; ask the office.

Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians.

Guide: How Medicare covers telehealth

Enrolled in Medicare (PECOS)

Dr. Seigrist has a Medicare enrollment record in PECOS, the CMS system clinicians use to enroll so they can bill Medicare or order services for people with Medicare.

It does not show whether the clinician accepts assignment, is in your plan's network, or is taking new patients.

Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.

Guide: What Medicare enrollment (PECOS) means

Can order Medicare-covered services

CMS lists Dr. Seigrist as eligible to order or refer Medicare Part B clinical laboratory and imaging services, durable medical equipment (DME) and home health services for people with Medicare.

What this does not show: Can order Medicare-covered services

It does not mean the clinician offers these services directly.

Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.

Guide: What ordering and referring status means

Compared with the same specialty in O Fallon and Illinois

5 active clinicians are listed under General Practice with a practice address in O Fallon, IL (291 in Illinois).

Addresses are self-reported to NPPES and may be out of date.

Sources: CMS Open Payments (2025), CMS Doctors and Clinicians, CMS NPPES NPI Registry. Specialty names follow the NUCC Health Care Provider Taxonomy.

Text: T-MedInfo Β· Report an error.

Pharma & Medical Device Financial Disclosures

Payments and other transfers of value that drug and medical device companies reported to CMS Open Payments

Open Payments Β· Program Year 2025

Program year 2025 (payments made January 1 – December 31, 2025): fewer than 11 records totaling $31.94.

Manufacturer Payment Nature Product Type Amount ($)
AstraZeneca Pharmaceuticals LP
Food and Beverage
In-kind items and services
BREZTRI General $31.94

Source: CMS Open Payments, program year 2025, released June 30, 2026.

Specialties & License Numbers Reported to NPPES

Self-certified to NPPES: 2026-06-24
General Practice Primary Specialty

NUCC Taxonomy Code: 208D00000X

License # reported to NPPES FL OS23985

A physician who specializes in the general practice of diagnosing, treating, and managing patients with a variety of illnesses and conditions.

Military Health Care Provider

NUCC Taxonomy Code: 171000000X

Active duty military health care providers not otherwise classified who need to be separately identified for operational, clinical, or administrative processes.

Student in an Organized Health Care Education/Training Program

NUCC Taxonomy Code: 390200000X

License # reported to NPPES IL 125.084301

An individual who is enrolled in an organized health care education/training program leading to a degree, certification, registration, and/or licensure to provide health care.

Check License Status with the State Board License numbers are self-reported to NPPES; T-MedInfo does not confirm them against state records. Current status: Illinois Department of Financial and Professional Regulation.
Look Up on State Board Site

Medicare (PECOS) Enrollment & Ordering Eligibility

Source: CMS PECOS
Medicare FFS Enrollment Status Medicare Enrollment on File
CMS Provider Specialty

ORDER AND REFERRING ONLY - FAMILY PRACTICE

Medicare Enrollment ID

I20241202002041

Enrollment State Jurisdiction

IL

PECOS Control ID

6406381383

Medicare Order & Referring Eligibility
Clinical Lab & Imaging (Part B) Eligible
Durable Medical Equipment (DME) Eligible
Home Health Agency (HHA) Eligible
Power Mobility Devices (PMD) Eligible

Sources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.

Clinicians Sharing This Practice Address or Phone

Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.

9 listed
NPI 1336424175

JANEAUXIER, Physician Assistant (Certified)

NPI 1265062178

Doctor of Medicine (M.D.)

Dr. Jill Coster , DO

Family Medicine

NPI 1205462942

Doctor of Osteopathic Medicine (D.O.)

NPI 1528120987

Doctor of Osteopathic Medicine (D.O.)

NPI 1912262007

Doctor of Pharmacy (Pharm.D.)

Dr. Ashley Gullixson , DO

Obstetrics & Gynecology

NPI 1992339584

Doctor of Osteopathic Medicine (D.O.)

Career & Practice History Timeline

Changes recorded in monthly NPPES data files: addresses, names, credentials, specialties and NPI status

12 Historical Events
πŸ“
Updated Practice Location June 09, 2024

Registered at 3 SAINT ELIZABETH BLVD STE 4000, O FALLON, IL 622691284 (Tel: 6182569355)

πŸ“
Updated Business Mailing Address June 09, 2024

Registered at 3 SAINT ELIZABETH BLVD STE 4000, O FALLON, IL 622691284 (Tel: 6182569355)

πŸ“
Updated Practice Location August 22, 2023

Registered at 3551 ROGER BROOKE DR, FORT SAM HOUSTON, TX 782344504 (Tel: 2109164141)

πŸ“
Updated Business Mailing Address August 22, 2023

Registered at 4306 LORING PARK, CONVERSE, TX 781093747 (Tel: 9726584680)

πŸ‘€
Provider Name / Credentials Updated August 22, 2023

Recorded as NATHAN SEIGRIST, DO

πŸŽ“
Medical Taxonomy / Specialty Registered (Primary Specialty) August 22, 2023

Military Health Care Provider

βœ…
NPI Profile Active February 21, 2023

NPI status registered as active in NPPES database

πŸ“
Practice Location (Initial Record) February 21, 2023

Registered at 5000 LAKEWOOD RANCH BLVD, BRADENTON, FL 342114909 (Tel: 9726584680)

πŸ“
Business Mailing Address (Initial Record) February 21, 2023

Registered at 4511 SUMMER COVE DR E APT 423, SARASOTA, FL 342434978 (Tel: 9726584680)

πŸ‘€
Provider Name / Credentials (Initial Record) February 21, 2023

Recorded as NATHAN SEIGRIST

πŸŽ“
Medical Taxonomy / Specialty Registered (Primary Specialty) February 21, 2023

Student in an Organized Health Care Education/Training Program

🟒
Initial NPI Registration & Enumeration February 21, 2023

First registered as active Individual Practitioner in NPPES Database.

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NPI Administrative Meta

NPI Number: 1780382465
Entity Type:
Individual Provider Physician, Nurse Practitioner, or Solo Healthcare Professional (Type 1 NPI)
Enumeration Date: February 21, 2023
Last Update: June 24, 2026
Sole Proprietor: Yes

Mailing Address

3 Saint Elizabeth Blvd Ste 4000

O Fallon, IL 622691284

Phone: 6182569355

About This Data NPPES fields (address, phone, specialty, license) are self-reported and may be outdated; Medicare fields follow the CMS dataset named in each section. Correct directly at NPPES.