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

Dr. Diana Lynn Theiss, PH.D., LISW-S

Clinical Social Worker in Sylvania, OH · enumerated 2011 · practices at Diana L Theiss Phd.

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

National Provider Identifier

1265722813

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Registry record

Entity type Individual (Type 1)
Name Dr. Diana Lynn Theiss
Credential PH.D., LISW-S
Sex Female
Practice address Sylvania, OH, 43560
Phone (419) 276-3556
Enumeration date Apr 17, 2011
Last updated in NPPES Mar 2, 2023

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

Taxonomy & licenses

104100000X Social Worker Behavioral Health & Social Service Providers · License I.0900183-SUPV (OH) Secondary
1041C0700X Clinical Social Worker Behavioral Health & Social Service Providers · License I-0900183-SUPV (OH) Primary
PHD · Doctor of Philosophy: A doctoral degree; in healthcare often held by clinical psychologists and researchers. About the PHD credential

Other identifiers

Identifier Type State Issuer
0155198 Medicaid OH -

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

Where does Diana Theiss practice?
The practice location on file with NPPES is in Sylvania, OH. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Diana Theiss?
The National Provider Identifier (NPI) for Diana Theiss is 1265722813, a Type 1 (individual) record in the CMS NPPES registry.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-03-02.