Medical emergency?Emergency? Call 911. Nearest emergency roomsNearest ERs

Nurse Practitioner

Caitlyn E. O'Brien, NP

Works at hospitals in Winchester, MA · Massachusetts

Summary

Caitlyn E. O'Brien, NP (Nurse Practitioner) is listed by Medicare at 1 hospital in Winchester, MA. NPI 1962100446. Medicare data says the clinician accepts Medicare assignment. Source: CMS Facility Affiliation Data, updated 2026-10-02.

From official Medicare data

This page shows what Medicare's official clinician data says about Caitlyn E. O'Brien, joined by NPI number (data updated 2026-10-02). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

At a glance

Nurse PractitionerPrimary specialty
YesAccepts Medicare assignment
4Years since medical school (graduated 2022)
FemaleGender (as listed)
Allergy and Asthma Physicians PCGroup practice

Quick answers

Which hospitals does Caitlyn E. O'Brien work at?
Medicare's official clinician data lists Caitlyn E. O'Brien at 1 hospital: Winchester Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
Where does Caitlyn E. O'Brien see patients?
Medicare's clinician data lists 1 practice location in Stoneham, MA. Call before your visit to confirm the address.
What is Caitlyn E. O'Brien's specialty?
Medicare lists Nurse Practitioner as the primary specialty.
Does Caitlyn E. O'Brien accept Medicare assignment?
Yes. Medicare's clinician data says Caitlyn E. O'Brien accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
What is the phone number for Caitlyn E. O'Brien?
(781) 395-2922, as listed in official Medicare / NPI Registry data.
What is Caitlyn E. O'Brien's NPI number?
1962100446. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Hospitals where Caitlyn E. O'Brien works

Medicare's Facility Affiliation Data lists Caitlyn E. O'Brien at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.

Practice locations

Addresses where Caitlyn E. O'Brien is enrolled with Medicare (CMS data updated 2026-10-02).

Group practices

Medicare enrollment lists Caitlyn E. O'Brien as a member of this group (CMS data updated 2026-10-02).

  • Allergy and Asthma Physicians PC5 clinicians in the group

Specialties

Find other clinicians: Nurse Practitioner, Massachusetts →

Other nurse practitioners in Stoneham

Clinicians with the same Medicare primary specialty in Stoneham, MA — not a recommendation.

All nurse practitioners in Stoneham →

Clinician information

CredentialNP
Graduation year2022
Gender (as listed)Female
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1962100446
CorrectionsReport an error or suggest an update →

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

  1. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated 2026-10-02, retrieved 2026-10-29
  2. National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
  3. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  4. Medicare Care Compare — official Medicare tool to look up clinicians