Quick answers
- Which hospitals does Walter Grenell work at?
- Medicare's official clinician data lists Walter Grenell at 1 hospital: BSA Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Walter Grenell see patients?
- Medicare's clinician data lists 1 practice location in Hilo, HI. Call before your visit to confirm the address.
- What is Walter Grenell's specialty?
- Medicare lists Emergency Medicine as the primary specialty.
- Does Walter Grenell accept Medicare assignment?
- Yes. Medicare's clinician data says Walter Grenell 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 Walter Grenell?
- (808) 974-6800, as listed in official Medicare / NPI Registry data.
- What is Walter Grenell's NPI number?
- 1669714994. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Walter Grenell works
Medicare's Facility Affiliation Data lists Walter Grenell at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- BSA HospitalAmarillo, TX · Acute Care Hospital · CCN 450231
Practice locations
Addresses where Walter Grenell is enrolled with Medicare (CMS data updated 2026-10-02).
- 1190 Waianuenue AveHilo, HI 96720 (808) 974‑6800
Group practices
Medicare enrollment lists Walter Grenell as a member of this group (CMS data updated 2026-10-02).
- Hawaii Emergency Physicians Associated Inc120 clinicians in the group
Specialties
- Emergency Medicineprimary
Other emergency medicine doctors in Hilo
Clinicians with the same Medicare primary specialty in Hilo, HI — not a recommendation.
Clinician information
| Credential | DO |
|---|---|
| Graduation year | 2013 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1669714994 |
| 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