Quick answers
- Which hospitals does John C. Messinger work at?
- Medicare's official clinician data lists John C. Messinger at 1 hospital: Zuckerberg San Francisco General Hosp & Trauma Ctr. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does John C. Messinger see patients?
- Medicare's clinician data lists 4 practice locations, including San Francisco, CA, Gualala, CA and Los Angeles, CA. Call before your visit to confirm the address.
- What is John C. Messinger's specialty?
- Medicare lists Internal Medicine as the primary specialty.
- Does John C. Messinger accept Medicare assignment?
- Medicare's clinician data says John C. Messinger may accept Medicare assignment (as of 2026-10-02). Ask the office whether they accept it for your visit.
- What is John C. Messinger's NPI number?
- 1588366579. 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 C. Messinger works
Medicare's Facility Affiliation Data lists John C. Messinger at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Zuckerberg San Francisco General Hosp & Trauma CtrSan Francisco, CA · Acute Care Hospital · CCN 050228
Practice locations
Addresses where John C. Messinger is enrolled with Medicare (CMS data updated 2026-10-02).
- 375 Laguna Honda BlvdSan Francisco, CA 94116
- 375 Laguna Honda Blvd, B200San Francisco, CA 94116
- 37880 Old Stage RdGualala, CA 95445
- PO BoxLos Angeles, CA 90074
Specialties
- Internal Medicineprimary
Other internal medicine doctors in San Francisco
Clinicians with the same Medicare primary specialty in San Francisco, CA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Harvard Medical School |
| Graduation year | 2023 |
| Gender (as listed) | Male |
| Medicare assignment | May accept for some services |
| NPI (National Provider Identifier) | 1588366579 |
| 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