Quick answers
- Which hospitals does John B. Siebenlist work at?
- Medicare's official clinician data lists John B. Siebenlist at 2 hospitals: French Hospital Medical Center and Marian Regional Medical Center. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does John B. Siebenlist see patients?
- Medicare's clinician data lists 1 practice location in Newport Beach, CA. Call before your visit to confirm the address.
- What is John B. Siebenlist's specialty?
- Medicare lists Dermatology as the primary specialty.
- Does John B. Siebenlist accept Medicare assignment?
- Yes. Medicare's clinician data says John B. Siebenlist accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
- What is the phone number for John B. Siebenlist?
- (949) 644-0101, as listed in official Medicare / NPI Registry data.
- What is John B. Siebenlist's NPI number?
- 1164476909. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where John B. Siebenlist works
Medicare's Facility Affiliation Data lists John B. Siebenlist at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- French Hospital Medical CenterSan Luis Obispo, CA · Acute Care Hospital · CCN 050232
- Marian Regional Medical CenterSanta Maria, CA · Acute Care Hospital · CCN 050107
Practice locations
Addresses where John B. Siebenlist is enrolled with Medicare (CMS data updated 2026-10-02).
- 400 Newport Ctr Dr, Suite 702Newport Beach, CA 92660 (949) 644‑0101
Group practices
Medicare enrollment lists John B. Siebenlist as a member of this group (CMS data updated 2026-10-02).
- J Robert West MD Inc138 clinicians in the group
Specialties
- Dermatologyprimary
Other dermatologists in Newport Beach
Clinicians with the same Medicare primary specialty in Newport Beach, CA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 1997 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1164476909 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians