Sebastian Niezen
NPI 1265162291 · Gastroenterology Physician · Boston, MA
Sebastian Niezen is a Gastroenterology Physician provider in Boston, MA (NPI 1265162291).
Provider details
- NPI number
- 1265162291
- Entity type
- Individual
- Primary specialty
- Gastroenterology PhysicianAllopathic & Osteopathic Physicians
- Sex
- Male
- Sole proprietor
- Yes
- License
- 3018049 (MA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
4 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
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
Registry dates
- Enumerated
- 2022-06-13
- Last updated
- 2025-06-30
- Certified
- 2025-06-30
Frequently asked questions
- What is Sebastian Niezen's NPI number?
- Sebastian Niezen's National Provider Identifier (NPI) is 1265162291, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Sebastian Niezen's specialty?
- Sebastian Niezen is listed in the NPPES registry with a primary specialty of Gastroenterology Physician (Allopathic & Osteopathic Physicians).
- Where is Sebastian Niezen located?
- Sebastian Niezen's practice location on file with NPPES is 330 Brookline Ave, Boston, MA 02215-5400.
- What is Sebastian Niezen's phone number?
- The practice phone number listed in the NPPES registry for Sebastian Niezen is (617) 480-3735.
- Is Sebastian Niezen's NPI active?
- Yes — Sebastian Niezen's NPI (1265162291) is active in the NPPES registry as of the last update on 2025-06-30.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.