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DR. ALEX NICHOLAS MUELLER MD
NPI 1235711938
Emergency Medicine in O Fallon, IL

Active since April 22, 2021PECOS EnrolledAccepts Medicare Assignment
1 SAINT ELIZABETH BLVD, O FALLON, IL 62269(618) 234-2120 Get Directions Write a Review

NPPES record last updated: August 11, 2026. Verified against the NPPES registry weekly; last sync: October 25, 2026.

Record update history: Aug 11, 2026, Jul 28, 2026, Mar 30, 2023 and 1 more (4 updates tracked since 2021).

About Dr. Alex Nicholas Mueller Md NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

DR. ALEX NICHOLAS MUELLER MD (NPI 1235711938) is an individual emergency medicine provider in O Fallon, Illinois, licensed in Illinois (036.180166) and active in the NPI registry since April 2021. He is enrolled in Medicare PECOS, is affiliated with Hshs St Elizabeth's Hospital, and is a graduate of Other (2023).

NPPES Registry Identity

NPI1235711938
Entity TypeIndividualMale
Primary Taxonomy207P00000X
Provider Legal NameDR. ALEX NICHOLAS MUELLERCredential: MD
Location Address1 SAINT ELIZABETH BLVDO Fallon, IL 62269-1099
Mailing Address1 Saint Elizabeth BlvdO Fallon, IL 62269-1099
Phone(618) 234-2120
Sole ProprietorYes
Medical School CMSOtherGraduated 2023
Enumeration DateApril 22, 2021
Last NPPES UpdateAugust 11, 20264 updates tracked since enumeration
NPPES CertifiedAugust 11, 2026
✔ NPI 1235711938 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyEmergency MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207P00000X
License✔ Licensed in IL · 036.180166
Definition
An emergency physician focuses on the immediate decision making and action necessary to prevent death or any further disability both in the pre-hospital setting by directing emergency medical technicians and in the emergency department. The emergency physician provides immediate recognition, evaluation, care, stabilization and disposition of a generally diversified population of adult and pediatric patients in response to acute illness and injury.
1 SAINT ELIZABETH BLVD, O Fallon, IL 62269
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Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Dr. Alex Nicholas Mueller Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID6204393002
PECOS Enrollment IDI20260812000971
Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignment

Medicare enrollment records show Alex Mueller reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Cepamerica Illinois LLP
0.8 mi
Emergency Medicine
1 SAINT ELIZABETH BLVD
O Fallon, IL 62269
  • Reassigned Medicare billing, Illinois enrollment
  • 982 clinicians in this Medicare group
NPI 1467951640 (618) 234-2120

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Hospital Affiliations CMS Care Compare

Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.

Hshs St Elizabeth's Hospital

Acute Care Hospitals · O Fallon, IL
4/5 CMS rating
OwnershipVoluntary non-profit - Church
CMS Certification Number140187
LocationOne St Elizabeth BoulevardO Fallon, IL 62269 · St. Clair County
Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 62269 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$88.44 typical visit price
range $56.28 – $173.35
Typical copayment $22.11 (range $14.07 – $43.33)
Most-billed visit code 99203
Established Patient
$99.71 typical visit price
range $17.51 – $139.99
Typical copayment $24.92 (range $4.37 – $34.99)
Most-billed visit code 99214
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

ST ELIZABETHS HOSPITAL OF THE HOSPITAL SISTERS OF THE THIRD ORDER
Rehabilitation Unit
1 SAINT ELIZABETH BLVD
O FALLON, IL 62269
St. Clair County (618) 234-2120
KATHRYN LOHMAN PA-C
Physician Assistant
1 SAINT ELIZABETH BLVD
O FALLON, IL 62269
St. Clair County (618) 234-2120
MS. SHAMBRA CULLUM APN
Nurse Practitioner (Family)
1 SAINT ELIZABETH BLVD
O FALLON, IL 62269
St. Clair County (217) 994-1485
ATA U. SIDDIQUI M.D.
Anesthesiology
1 SAINT ELIZABETH BLVD
O FALLON, IL 62269
St. Clair County (618) 234-2120
DR. VINCENT JOSEPH DUENAS MD
Hospitalist
1 SAINT ELIZABETH BLVD
O FALLON, IL 62269
St. Clair County (618) 234-2120
CAITLIN ALONZO
Nurse Practitioner
1 SAINT ELIZABETH BLVD
O FALLON, IL 62269
St. Clair County (618) 234-2120
CEP AMERICA-ILLINOIS HOSPITALISTS, LLP
Internal Medicine
1 SAINT ELIZABETH BLVD
O FALLON, IL 62269
St. Clair County (618) 234-2120
JENNIFER L CRIPPS CRNA
Nurse Anesthetist, Certified Registered
1 SAINT ELIZABETH BLVD
O FALLON, IL 62269
St. Clair County (618) 234-2120

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Alex Mueller's NPI number?

The NPI number for Alex Mueller is 1235711938. It was assigned to this individual provider in the NPPES registry on April 22, 2021.

Where is Alex Mueller located?

Alex Mueller practices at 1 Saint Elizabeth Blvd, O Fallon, IL 62269. The listed phone number is (618) 234-2120.

What is Alex Mueller's specialty?

The primary specialty registered for this NPI is Emergency Medicine with taxonomy code 207P00000X.

Is Alex Mueller enrolled in Medicare?

Yes. Alex Mueller is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

Which organization bills Medicare for Alex Mueller's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Alex Mueller reassigns Medicare benefits to Cepamerica Illinois LLP (O Fallon, IL). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Alex Mueller's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

Is Alex Mueller affiliated with any hospitals?

According to CMS data, Alex Mueller is affiliated with Hshs St Elizabeth's Hospital.

When was this NPI record last updated?

The NPPES record for Alex Mueller was last updated on August 11, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 2 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.