Quick answers
- Where does John A. Gnassi see patients?
- Medicare's clinician data lists 2 practice locations, including Leupp, AZ and Winslow, AZ. Call before your visit to confirm the address.
- What is John A. Gnassi's specialty?
- Medicare lists Hospitalist as the primary specialty.
- Does John A. Gnassi accept Medicare assignment?
- Yes. Medicare's clinician data says John A. Gnassi 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 A. Gnassi?
- (928) 289-4646, as listed in official Medicare / NPI Registry data.
- What is John A. Gnassi's NPI number?
- 1629066105. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Practice locations
Addresses where John A. Gnassi is enrolled with Medicare (CMS data updated 2026-10-02).
- 1 5 Miles N of Leupp Chapter House, Leupp Health StationLeupp, AZ 86035 (928) 289‑4646
- 1501 N Williamson Ave, Little Colorado Medical CenterWinslow, AZ 86047 (928) 289‑4646
Group practices
Medicare enrollment lists John A. Gnassi as a member of this group (CMS data updated 2026-10-02).
- Winslow Indian Health Care Center Inc100 clinicians in the group
Specialties
- Hospitalistprimary
Other hospitalists in Arizona
Clinicians with the same Medicare primary specialty in Arizona — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Rutgers R W Johnson Medical School (cam/new Bruns/pisc) |
| Graduation year | 1988 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1629066105 |
| 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
- 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