CAITLIN O'CALLAGHAN REEN NP
NPI 1033391685
Nurse Practitioner - Adult Health in Boston, MA
About Caitlin O'callaghan Reen Np NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
CAITLIN O'CALLAGHAN REEN NP (NPI 1033391685) is an individual adult health provider in Boston, Massachusetts, licensed in Massachusetts (256018) and active in the NPI registry since December 2007. She is enrolled in Medicare PECOS, is affiliated with North Shore Medical Center -, and is a graduate of Other (2007).
NPPES Registry Identity
Specialties & Licenses
Accepted Insurance
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 O'callaghan Reen Np 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.
Medicare Billing Reassignments
3Medicare enrollment records show Caitlin Reen reassigns Medicare billing to 3 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Boston, MA 02114
- Reassigned Medicare billing, Massachusetts enrollment
- 6,360 clinicians in this Medicare group
Boston, MA 02114
- Reassigned Medicare billing, Massachusetts enrollment
- 6,234 clinicians in this Medicare group
Dallas, TX 75244
- Reassigned Medicare billing, Massachusetts enrollment
- 203 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims 4
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Hospital Affiliations CMS Care Compare 5
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
North Shore Medical Center -
Acute Care Hospitals · Salem, MAMassachusetts General Hospital
Acute Care Hospitals · Boston, MANewton-Wellesley Hospital
Acute Care Hospitals · Newton, MABrigham And Women's Hospital
Acute Care Hospitals · Boston, MAMartha's Vineyard Hospital Inc
Critical Access Hospitals · Oak Bluffs, MAPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 02114 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
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.
BOSTON, MA 02114
BOSTON, MA 02114
BOSTON, MA 02114
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 Reen's NPI number?
The NPI number for Caitlin Reen is 1033391685. It was assigned to this individual provider in the NPPES registry on December 5, 2007.
Where is Caitlin Reen located?
Caitlin Reen practices at 55 Fruit St Gray / Bigelow 800, Mailstop 843, Boston, MA 02114. The listed phone number is (617) 724-0122.
What is Caitlin Reen's specialty?
The primary specialty registered for this NPI is Nurse Practitioner, specializing in Adult Health, with taxonomy code 363LA2200X.
Is Caitlin Reen enrolled in Medicare?
Yes. Caitlin Reen 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 organizations bill Medicare for Caitlin Reen's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Caitlin Reen reassigns Medicare benefits to 3 organizations: Massachusetts General Physicians Organization Inc (Boston, MA), The General Hospital Corporation (Boston, MA) and Signify Health Medical Associates, PLLC (Dallas, TX). Each 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 Reen's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Caitlin Reen accept?
Health plans from CareSource (Common Ground Healthcare) list Caitlin Reen as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
Is Caitlin Reen affiliated with any hospitals?
According to CMS data, Caitlin Reen is affiliated with North Shore Medical Center -, Massachusetts General Hospital, Newton-Wellesley Hospital, Brigham And Women's Hospital and Martha's Vineyard Hospital Inc.
When was this NPI record last updated?
The NPPES record for Caitlin Reen was last updated on February 18, 2016. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 years 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.
# Caitlin O'callaghan Reen, NP · NPI 1033391685
Adult Health physician in Boston, Massachusetts. Individual provider, active in the CMS NPPES registry since December 5, 2007.
## Identity
- **NPI:** 1033391685 (Entity type: Individual)
- **Enumerated:** December 5, 2007
- **Primary specialty:** Nurse Practitioner - Adult Health · taxonomy 363LA2200X
- **State license:** 256018 (Massachusetts)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 55 FRUIT ST, GRAY / BIGELOW 800, MAILSTOP 843, Boston, MA 02114-2621
- **Phone:** (617) 724-0122
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 3 organizations under Medicare reassignment (form CMS-855R): Massachusetts General Physicians Organization Inc (NPI 1801874573, Boston, MA); The General Hospital Corporation (NPI 1023049236, Boston, MA); Signify Health Medical Associates, PLLC (NPI 1750845863, Dallas, TX) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2007
## Record status
- **NPPES last updated:** February 18, 2016
---
Source: [NPI Profile](https://npiprofile.com/npi/1033391685) · Data from the CMS NPPES public registry.