Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Caitlin Alonzo
Nurse Practitioner in O Fallon, IL · enumerated 2025.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1083576243
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Registry record
Entity type Individual (Type 1)
Name Caitlin Alonzo
Sex Female
Practice address 1 Saint Elizabeth Blvd, O Fallon, IL, 62269
Phone (618) 234-2120
Enumeration date Nov 26, 2025
Last updated in NPPES Mar 23, 2026
Taxonomy & licenses
363L00000X Nurse Practitioner Physician Assistants & Advanced Practice Nursing Providers · License 209034125 (IL) Primary
363LF0000X Family Nurse Practitioner Physician Assistants & Advanced Practice Nursing Providers · License 2025008810 (MO) Secondary
What is an NPI number?
A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.
Frequently asked questions
Where does Caitlin Alonzo practice?
The practice location on file with NPPES is in O Fallon, IL. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Caitlin Alonzo?
The National Provider Identifier (NPI) for Caitlin Alonzo is 1083576243, a Type 1 (individual) record in the CMS NPPES registry.
Other providers at this practice address
Browse all → Ata Siddiqui Anesthesiology Physician · O Fallon, IL NPI 1043206618 Edward Schuessler Anesthesiology Physician · O Fallon, IL NPI 1811976707 St Elizabeths Hospital of the Hospital Sisters of the Third Order General Acute Care Hospital · O Fallon, IL NPI 1629057302 St Elizabeths Hospital of the Hospital Sisters of the Third Order Rehabilitation Hospital Unit · O Fallon, IL NPI 1023097540 Ssm Cardinal Glennon Childrens Hospital Pediatrics Physician · O Fallon, IL NPI 1174577670 Gregory Bray-Stanley Anesthesiology Physician · O Fallon, IL NPI 1902836679 Bryon Gorton Specialist · O Fallon, IL NPI 1366500910 Margaret Schuch Certified Registered Nurse Anesthetist · O Fallon, IL NPI 1932247707
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2026-03-23.