Quick answers
- Which hospitals does John Diana work at?
- Medicare's official clinician data lists John Diana at 5 hospitals: Adventist Health Clearlake, Adventist Health St Helena, Mad River Community Hospital, Providence Queen of the Valley Medical Center and Sonoma Valley Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does John Diana see patients?
- Medicare's clinician data lists 3 practice locations, including Saint Helena, CA and Napa, CA. Call before your visit to confirm the address.
- What is John Diana's specialty?
- Medicare lists Orthopedic Surgery as the primary specialty.
- Does John Diana accept Medicare assignment?
- Yes. Medicare's clinician data says John Diana 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 Diana?
- (707) 963-3611, as listed in official Medicare / NPI Registry data.
- What is John Diana's NPI number?
- 1649297540. 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 Diana works
Medicare's Facility Affiliation Data lists John Diana at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Adventist Health ClearlakeClearlake, CA · Critical Access Hospital · CCN 051317
- Adventist Health St HelenaSaint Helena, CA · Acute Care Hospital · CCN 050013
- Mad River Community HospitalArcata, CA · Acute Care Hospital · CCN 050028
- Providence Queen of the Valley Medical CenterNapa, CA · Acute Care Hospital · CCN 050009
- Sonoma Valley HospitalSonoma, CA · Acute Care Hospital · CCN 050090
Practice locations
Addresses where John Diana is enrolled with Medicare (CMS data updated 2026-10-02).
- 10 Woodland RdSaint Helena, CA 94574 (707) 963‑3611
- 3273 Claremont Way, Suite 100Napa, CA 94558 (707) 254‑7117
- 6 Woodland Rd, Suite 202Saint Helena, CA 94574 (707) 968‑0670
Group practices
Medicare enrollment lists John Diana as a member of these groups (CMS data updated 2026-10-02).
- St. Helena Hospital84 clinicians in the group
- Napa Valley Orthopaedic Medical Group Inc17 clinicians in the group
Specialties
- Orthopedic Surgeryprimary
Other orthopedic surgeons in Saint Helena
Clinicians with the same Medicare primary specialty in Saint Helena, CA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Indiana University School Of Medicine |
| Graduation year | 1996 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1649297540 |
| 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