DR. AARON BARAK NEINSTEIN MD
NPI 1205074028
Internal Medicine - Endocrinology, Diabetes & Metabolism in San Francisco, CA
About Dr. Aaron Barak Neinstein Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. AARON BARAK NEINSTEIN MD (NPI 1205074028) is an individual endocrinology, diabetes & metabolism provider in San Francisco, California, licensed in California (A106501) and active in the NPI registry since February 2009. He is enrolled in Medicare PECOS and is a graduate of University Of Southern California Keck School Of Medicine (2007).
NPPES Registry Identity
Specialties & Licenses 2
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Dr. Aaron Barak Neinstein Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignments
2Medicare enrollment records show Aaron Neinstein reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
San Francisco, CA 94143
- Reassigned Medicare billing, California enrollment
- 5,645 clinicians in this Medicare group
San Francisco, CA 94143
- Reassigned Medicare billing, California enrollment
- 2,112 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 94143 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Referred Medical Equipment & Supplies CMS DME claims 2
Durable medical equipment, devices and supplies this provider ordered from DME suppliers for patients, from Medicare fee-for-service claims.
Other Providers at the Same Location NPPES 8
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Aaron Neinstein's NPI number?
The NPI number for Aaron Neinstein is 1205074028. It was assigned to this individual provider in the NPPES registry on February 2, 2009.
Where is Aaron Neinstein located?
Aaron Neinstein practices at 400 Parnassus Avenue Ste A550, San Francisco, CA 94143. The listed phone number is (415) 353-2350.
What is Aaron Neinstein's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Endocrinology, Diabetes & Metabolism, with taxonomy code 207RE0101X.
Is Aaron Neinstein enrolled in Medicare?
Yes. Aaron Neinstein is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organizations bill Medicare for Aaron Neinstein's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Aaron Neinstein reassigns Medicare benefits to 2 organizations: University Of California San Francisco (San Francisco, CA) and Regents Of The University Of California (San Francisco, CA). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Aaron Neinstein's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
When was this NPI record last updated?
The NPPES record for Aaron Neinstein was last updated on May 15, 2018. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 8 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Dr. Aaron Barak Neinstein, MD · NPI 1205074028
Endocrinology, Diabetes & Metabolism physician in San Francisco, California. Individual provider, active in the CMS NPPES registry since February 2, 2009.
## Identity
- **NPI:** 1205074028 (Entity type: Individual)
- **Enumerated:** February 2, 2009
- **Primary specialty:** Internal Medicine - Endocrinology, Diabetes & Metabolism · taxonomy 207RE0101X
- **State license:** A106501 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 400 PARNASSUS AVENUE, STE A550, San Francisco, CA 94143
- **Phone:** (415) 353-2350 · **Fax:** (415) 353-2337
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 2 organizations under Medicare reassignment (form CMS-855R): University Of California San Francisco (NPI 1346329380, San Francisco, CA); Regents Of The University Of California (NPI 1376613943, San Francisco, CA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** University Of Southern California Keck School Of Medicine, class of 2007
## Record status
- **NPPES last updated:** May 15, 2018
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Source: [NPI Profile](https://npiprofile.com/npi/1205074028) · Data from the CMS NPPES public registry.