Jonathan Grein, MD
NPI 1295956092 · Internal Medicine Physician · Los Angeles, CA
Enrolled with Medicare as Practitioner - Infectious Disease · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Jonathan Grein, MD is a Internal Medicine Physician provider in Los Angeles, CA (NPI 1295956092).
Provider details
- NPI number
- 1295956092
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- Yes
- License
- A94549 (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
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
- 2007-05-01
- Last updated
- 2010-03-23
Frequently asked questions
- What is Jonathan Grein's NPI number?
- Jonathan Grein's National Provider Identifier (NPI) is 1295956092, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Jonathan Grein's specialty?
- Jonathan Grein is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Jonathan Grein located?
- Jonathan Grein's practice location on file with NPPES is 8635 W 3rd St, Los Angeles, CA 90048-6101.
- What is Jonathan Grein's phone number?
- The practice phone number listed in the NPPES registry for Jonathan Grein is (310) 423-5574.
- Does Jonathan Grein accept Medicare?
- Jonathan Grein is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Jonathan Grein's NPI active?
- Yes — Jonathan Grein's NPI (1295956092) is active in the NPPES registry as of the last update on 2010-03-23.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.