Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Delwyn Lee Lassen, MD

Family Medicine Physician in Sioux Center, IA · enumerated 2005 · practices at Greater Sioux Community Health Center Inc..

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

National Provider Identifier

1558346015

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Registry record

Entity type Individual (Type 1)

Name Delwyn Lee Lassen

Credential MD

Sex Male

Practice address 33 4th St Nw, Sioux Center, IA, 51250

Phone (712) 722-1700

Fax (712) 722-1770

Enumeration date Dec 7, 2005

Last updated in NPPES Dec 15, 2020

Taxonomy & licenses

207Q00000X Family Medicine Physician Allopathic & Osteopathic Physicians · License 21150 (IA) 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
1336127828	Other	-	GROUP NPI
1066548	Medicaid	IA	-

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 Delwyn Lassen practice?

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

What is the NPI number for Delwyn Lassen?

The National Provider Identifier (NPI) for Delwyn Lassen is 1558346015, a Type 1 (individual) record in the CMS NPPES registry.

Other providers at this practice address

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2020-12-15.