Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Alexandra Leong Mattern
Clinical Psychologist in Boston, MA · enumerated 2023.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1306529276
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Registry record
Entity type Individual (Type 1)
Name Alexandra Leong Mattern
Sex Female
Practice address 150 S Huntington Ave, Boston, MA, 02130
Phone (857) 364-4126
Enumeration date Aug 8, 2023
Last updated in NPPES Aug 8, 2023
Taxonomy & licenses
103TC0700X Clinical Psychologist Behavioral Health & Social Service Providers · License PSY10000112 (MA) Primary
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
What is the NPI number for Alexandra Leong Mattern?
The National Provider Identifier (NPI) for Alexandra Leong Mattern is 1306529276, a Type 1 (individual) record in the CMS NPPES registry.
Where does Alexandra Leong Mattern practice?
The practice location on file with NPPES is in Boston, MA. Providers can have multiple locations; NPPES lists the primary practice address.
Other providers at this practice address
Browse all → Thomas Fantes Family Medicine Physician · Boston, MA NPI 1972500429 Elisabeth Buchanan Social Worker · Boston, MA NPI 1285636159 Edward Lew Gastroenterology Physician · Jamaica Plain, MA NPI 1376526459 Michael Dawes Psychiatry Physician · Boston, MA NPI 1841274594 Barbara Cooper Clinical Psychologist · Boston, MA NPI 1720063084 Joseph Rafferty Family Medicine Physician · Boston, MA NPI 1669459723 Nhan Do Internal Medicine Physician · Boston, MA NPI 1750353967 Christopher Conroy Physical Therapist · Boston, MA NPI 1942273495
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-08-08.