Dr. Jonathan A Leff, M.D.
Dr. Jonathan A Leff is a Research Study Specialist provider (Specialist) practicing in Menlo Park, CA, registered in the NPPES registry with NPI 1538407721 since 2013. The credential MD stands for Doctor of Medicine.
✓ Active NPI ✓ Valid NPI checksum Sole proprietor
| NPI | 1538407721 |
|---|---|
| Entity type | Individual (Type 1) |
| Name | Dr. Jonathan A Leff |
| Credential | M.D. |
| Sex | Male |
| Practice address | Menlo Park, CA, 94025 |
| Phone | 6505210353 |
| Enumeration date | 2013-01-22 |
| Last updated in NPPES | 2013-01-22 |
Street address withheld — NPPES sole-proprietor addresses can be home addresses. See our data policy.
Taxonomy & licenses
| Taxonomy code | Specialty | Primary | License | State |
|---|---|---|---|---|
| 1744R1102X | Research Study Specialist | Primary | G86872 | CA |
MD — Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential
Copy-ready billing details
Provider: Jonathan Leff, M.D. NPI: 1538407721 Taxonomy: 1744R1102X (Research Study Specialist) Address: Menlo Park, CA, 94025
Verify this record
Cross-check NPI 1538407721 against the authoritative CMS record: view Dr. Jonathan A Leff on the official NPPES registry .
What is an NPI number?
A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes — even if the provider moves or changes specialty. Read the full guide or validate an NPI number.
Frequently asked questions
Is NPI 1538407721 active?
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Source: CMS NPPES (public data). Snapshot 2026-07-11. Provider record last updated 2013-01-22.