NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Jan E Leyden, M.D.

Student in an Organized Health Care Education/Training Program in Brookline, MA · enumerated 2009.

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

National Provider Identifier

1821236852

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Registry record

Entity type Individual (Type 1)
Name Jan E Leyden
Credential M.D.
Sex Male
Practice address Brookline, MA, 02445
Phone (617) 708-4568
Enumeration date Jan 29, 2009
Last updated in NPPES Jan 29, 2009

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

390200000X Student in an Organized Health Care Education/Training Program Student, Health Care · License 238315 (MA) Primary
MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD 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.

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Frequently asked questions

What is the NPI number for Jan Leyden?
The National Provider Identifier (NPI) for Jan Leyden is 1821236852, a Type 1 (individual) record in the CMS NPPES registry.
Where does Jan Leyden practice?
The practice location on file with NPPES is in Brookline, MA. Providers can have multiple locations; NPPES lists the primary practice address.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2009-01-29.