Delwyn Lassen, MD
NPI 1558346015 · Family Medicine Physician · Sioux Center, IA
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Delwyn Lassen, MD is a Family Medicine Physician provider in Sioux Center, IA (NPI 1558346015).
Provider details
- NPI number
- 1558346015
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 21150 (IA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
20 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
2 documented practice locations
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
Practice location
Mailing address
Additional practice locations (1)
- 2501 Pierce StSioux City, IA 51104-3725Phone: (712) 294-5000Fax: (712) 294-5091
Registry dates
- Enumerated
- 2005-12-07
- Last updated
- 2020-12-15
- Certified
- 2020-12-15
Frequently asked questions
- What is Delwyn Lassen's NPI number?
- Delwyn Lassen's National Provider Identifier (NPI) is 1558346015, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Delwyn Lassen's specialty?
- Delwyn Lassen is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Delwyn Lassen located?
- Delwyn Lassen's practice location on file with NPPES is 33 4th St Nw, Sioux Center, IA 51250-1870.
- What is Delwyn Lassen's phone number?
- The practice phone number listed in the NPPES registry for Delwyn Lassen is (712) 722-1700.
- Does Delwyn Lassen accept Medicare?
- Delwyn Lassen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Delwyn Lassen's NPI active?
- Yes — Delwyn Lassen's NPI (1558346015) is active in the NPPES registry as of the last update on 2020-12-15.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.