Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Abby Muehlstein, LCSW

Social Worker in Boston, MA · enumerated 2025.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1104701721

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Registry record

Entity type Individual (Type 1)

Name Abby Muehlstein

Credential LCSW

Sex Female

Practice address 300 Longwood Ave, Boston, MA, 02115

Phone (617) 355-6000

Enumeration date Aug 11, 2025

Last updated in NPPES Aug 11, 2025

Taxonomy & licenses

104100000X Social Worker Behavioral Health & Social Service Providers · License LCSW2120188 (MA) Primary

LCSW · Licensed Clinical Social Worker: A social worker licensed for clinical practice including mental-health therapy. About the LCSW credential

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.

Read the full guide → Validate an NPI →

Frequently asked questions

Is NPI 1104701721 active?

Yes, as of the latest NPPES snapshot, NPI 1104701721 is active (record last updated 2025-08-11).

How do I verify Abby Muehlstein's NPI record?

Cross-check NPI 1104701721 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2025-08-11.