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

Diane Kristina Witmer, LCSW

Q: What is the NPI number for Diane Witmer?

The National Provider Identifier (NPI) for Diane Witmer is 1033771225, a Type 1 (individual) record in the CMS NPPES registry.

Clinical Social Worker in East Islip, NY · enumerated 2019.

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

National Provider Identifier

1033771225

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Registry record

Entity type Individual (Type 1)

Name Diane Kristina Witmer

Credential LCSW

Sex Female

Practice address East Islip, NY, 11730

Phone (631) 338-3913

Enumeration date Jul 8, 2019

Last updated in NPPES Nov 27, 2023

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

Taxonomy & licenses

1041C0700X Clinical Social Worker Behavioral Health & Social Service Providers · License 088174 (NY) Secondary

1041C0700X Clinical Social Worker Behavioral Health & Social Service Providers · License 0904011127 (VA) Secondary

1041C0700X Clinical Social Worker Behavioral Health & Social Service Providers · License 7058 (TN) 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

Where does Diane Witmer practice?

The practice location on file with NPPES is in East Islip, NY. Providers can have multiple locations; NPPES lists the primary practice address.

What is the NPI number for Diane Witmer?

The National Provider Identifier (NPI) for Diane Witmer is 1033771225, a Type 1 (individual) record in the CMS NPPES registry.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-11-27.