Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Mr. Robert E Greenspan, MD

Nephrology Physician in Fairfax, VA · enumerated 2005.

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

National Provider Identifier

1811995467

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Registry record

Entity type Individual (Type 1)

Name Mr. Robert E Greenspan

Credential MD

Sex Male

Practice address 13135 Lee Jackson Memorial Hwy, 135, Fairfax, VA, 22033

Phone (703) 961-0488

Fax (703) 961-0480

Enumeration date Jul 8, 2005

Last updated in NPPES Aug 11, 2016

Taxonomy & licenses

207RN0300X Nephrology Physician Allopathic & Osteopathic Physicians · License 0101029580 (VA) Primary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier	Type	State	Issuer
006087752	Medicaid	VA	-

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

Is this the official NPI registry?

No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

What specialty is Robert Greenspan?

Robert Greenspan is registered in NPPES with the primary taxonomy of Nephrology Physician. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2016-08-11.