1. Home
  2. Directory
  3. Illinois
  4. O Fallon
  5. Nurse Practitioner
  6. NPI Profile

CAITLIN ALONZO
NPI 1083576243
Nurse Practitioner in O Fallon, IL

Active since November 26, 2025PECOS EnrolledAccepts Medicare Assignment
1 SAINT ELIZABETH BLVD, O FALLON, IL 62269(618) 234-2120 Get Directions Write a Review

NPPES record last updated: March 23, 2026. Verified against the NPPES registry weekly; last sync: October 25, 2026.

Record update history: Mar 23, 2026, Nov 26, 2025 (2 updates tracked since 2025).

About Caitlin Alonzo NPPES

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

CAITLIN ALONZO (NPI 1083576243) is an individual nurse practitioner in O Fallon, Illinois, licensed in Illinois (209034125) and active in the NPI registry since November 2025. She is enrolled in Medicare PECOS, is affiliated with St Josephs Hospital, and is a graduate of Other (2018).

NPPES Registry Identity

NPI1083576243
Entity TypeIndividualFemale
Primary Taxonomy363L00000X
Provider Legal NameCAITLIN ALONZO
Location Address1 SAINT ELIZABETH BLVDO Fallon, IL 62269-1099
Mailing Address212 Harbor VwFenton, MO 63026-7515
Phone(618) 234-2120
Sole ProprietorNo
Medical School CMSOtherGraduated 2018
Enumeration DateNovember 26, 2025
Last NPPES UpdateMarch 23, 20262 updates tracked since enumeration
NPPES CertifiedMarch 23, 2026
✔ NPI 1083576243 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyNurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers
Taxonomy Code363L00000X
License✔ Licensed in IL · 209034125
Definition
(1) A registered nurse provider with a graduate degree in nursing prepared for advanced practice involving independent and interdependent decision making and direct accountability for clinical judgment across the health care continuum or in a certified specialty. (2) A registered nurse who has completed additional training beyond basic nursing education and who provides primary health care services in accordance with state nurse practice laws or statutes. Tasks performed by nurse practitioners vary with practice requirements mandated by geographic, political, economic, and social factors. Nurse practitioner specialists include, but are not limited to, family nurse practitioners, gerontological nurse practitioners, pediatric nurse practitioners, obstetric-gynecologic nurse practitioners, and school nurse practitioners.
Also ListedNurse Practitioner · FamilyTaxonomy 363LF0000X · License 2025008810 (MO)
1 SAINT ELIZABETH BLVD, O Fallon, IL 62269
Open in Google Maps ↗

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

Caitlin Alonzo 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 ID9638652118
PECOS Enrollment IDI20260312002165
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 Caitlin Alonzo reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Cep America-Illinois Hospitalists, LLP
1.6 mi
Internal Medicine
1404 CROSS ST
Shiloh, IL 62269
  • Reassigned Medicare billing, Illinois enrollment
  • 329 clinicians in this Medicare group
NPI 1619335106 (618) 233-7750

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 3

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

St Josephs Hospital

Acute Care Hospitals · Breese, IL
OwnershipVoluntary non-profit - Church
CMS Certification Number140145
Location9515 Holy Cross LnBreese, IL 62230 · Clinton County
Emergency services Birthing friendly

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

St Joseph's Hospital

Critical Access Hospitals · Highland, IL
3/5 CMS rating
OwnershipVoluntary non-profit - Church
CMS Certification Number141336
Location12866 Troxler AvenueHighland, IL 62249 · Madison County
Emergency services

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
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
DR. KIMBERLY ELISE PORTALE D.O.
Obstetrics & Gynecology
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 Caitlin Alonzo's NPI number?

The NPI number for Caitlin Alonzo is 1083576243. It was assigned to this individual provider in the NPPES registry on November 26, 2025.

Where is Caitlin Alonzo located?

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

What is Caitlin Alonzo's specialty?

The primary specialty registered for this NPI is Nurse Practitioner with taxonomy code 363L00000X.

Is Caitlin Alonzo enrolled in Medicare?

Yes. Caitlin Alonzo 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 Caitlin Alonzo's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Caitlin Alonzo reassigns Medicare benefits to Cep America-Illinois Hospitalists, LLP (Shiloh, 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 Caitlin Alonzo's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

Is Caitlin Alonzo affiliated with any hospitals?

According to CMS data, Caitlin Alonzo is affiliated with St Josephs Hospital, Hshs St Elizabeth's Hospital and St Joseph's Hospital.

When was this NPI record last updated?

The NPPES record for Caitlin Alonzo was last updated on March 23, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 7 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.