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

Dr. Joyce Fivehouse Derby, PH.D.

Q: What is the NPI number for Joyce Derby?

The National Provider Identifier (NPI) for Joyce Derby is 1538200399, a Type 1 (individual) record in the CMS NPPES registry.

Psychologist in Olney, MD · enumerated 2007.

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

National Provider Identifier

1538200399

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Registry record

Entity type Individual (Type 1)

Name Dr. Joyce Fivehouse Derby

Credential PH.D.

Sex Female

Practice address Olney, MD, 20832

Phone (301) 570-7500

Enumeration date Feb 12, 2007

Last updated in NPPES Sep 11, 2025

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

Taxonomy & licenses

103TC0700X Clinical Psychologist Behavioral Health & Social Service Providers · License 03079 (MD) Secondary

103TC2200X Clinical Child & Adolescent Psychologist Behavioral Health & Social Service Providers · License 03079 (MD) Secondary

103T00000X Psychologist Behavioral Health & Social Service Providers · License 03079 (MD) 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
124466	Other	MD	APS
3838 0001	Other	MH	BLUE CROSS BLUE SHIELD

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 Joyce Derby practice?

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

What is the NPI number for Joyce Derby?

The National Provider Identifier (NPI) for Joyce Derby is 1538200399, a Type 1 (individual) record in the CMS NPPES registry.

Other providers at this practice address

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Gerald Oster Psychologist · Olney, MD NPI 1528181906 Lori Post Clinical Social Worker · Olney, MD NPI 1962602391 Kamakshi Boyle Clinical Social Worker · Olney, MD NPI 1598920027 Robin Blumberg Professional Counselor · Olney, MD NPI 1194022897

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2025-09-11.