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Mark Allendorph, M.D.
NPI 1922094002 · Gastroenterology Physician · Alton, IL
Mark Allendorph, M.D. is a Gastroenterology Physician provider in Alton, IL (NPI 1922094002).
Provider details
- NPI number
- 1922094002
- Entity type
- Individual
- Primary specialty
- Gastroenterology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- 036072597 (IL)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
Detailed profile(91/100 index)
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
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
2 Memorial Dr
Suite 205
Alton, IL 62002-6723
Phone: (618) 465-5849
Fax: (618) 465-5853
Street-level locationGet directions
Mailing address
2 Memorial Dr
Alton, IL 62002-6723
Registry dates
- Enumerated
- 2005-09-23
- Last updated
- 2008-05-27
Frequently asked questions
- What is Mark Allendorph's NPI number?
- Mark Allendorph's National Provider Identifier (NPI) is 1922094002, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Allendorph's specialty?
- Mark Allendorph is listed in the NPPES registry with a primary specialty of Gastroenterology Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Allendorph located?
- Mark Allendorph's practice location on file with NPPES is 2 Memorial Dr, Alton, IL 62002-6723.
- What is Mark Allendorph's phone number?
- The practice phone number listed in the NPPES registry for Mark Allendorph is (618) 465-5849.
- Is Mark Allendorph's NPI active?
- Yes — Mark Allendorph's NPI (1922094002) is active in the NPPES registry as of the last update on 2008-05-27.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.