Mark Clark, MD
NPI 1891874665 · Internal Medicine Physician · Glendale, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Clark, MD is a Internal Medicine Physician provider in Glendale, CA (NPI 1891874665).
Provider details
- NPI number
- 1891874665
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- G50527 (CA)
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
19 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)
- 840 Irving StSan Francisco, CA 94122-2311Phone: (888) 663-6331Fax: (415) 252-7176
Registry dates
- Enumerated
- 2006-11-03
- Last updated
- 2025-11-18
- Certified
- 2025-11-18
Frequently asked questions
- What is Mark Clark's NPI number?
- Mark Clark's National Provider Identifier (NPI) is 1891874665, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Clark's specialty?
- Mark Clark is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Clark located?
- Mark Clark's practice location on file with NPPES is 3746 Foothill Blvd # B140, Glendale, CA 91214-1740.
- What is Mark Clark's phone number?
- The practice phone number listed in the NPPES registry for Mark Clark is (310) 445-5999.
- Does Mark Clark accept Medicare?
- Mark Clark is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Clark's NPI active?
- Yes — Mark Clark's NPI (1891874665) is active in the NPPES registry as of the last update on 2025-11-18.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.