Quick answers
- Which hospitals does Joshua K. Greenstein work at?
- Medicare's official clinician data lists Joshua K. Greenstein at 2 hospitals: Palomar Health Downtown Campus and Palomar Medical Center Poway. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Joshua K. Greenstein see patients?
- Medicare's clinician data lists 7 practice locations, including Fountain Valley, CA, San Diego, CA and Escondido, CA. Call before your visit to confirm the address.
- What is Joshua K. Greenstein's specialty?
- Medicare lists Nephrology as the primary specialty.
- Does Joshua K. Greenstein accept Medicare assignment?
- Yes. Medicare's clinician data says Joshua K. Greenstein 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.
- Does Joshua K. Greenstein offer telehealth?
- Medicare's clinician data says Joshua K. Greenstein offers telehealth services. Ask the office which visits can be done by video or phone.
- What is the phone number for Joshua K. Greenstein?
- (714) 641-9696, as listed in official Medicare / NPI Registry data.
- What is Joshua K. Greenstein's NPI number?
- 1104881457. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Joshua K. Greenstein works
Medicare's Facility Affiliation Data lists Joshua K. Greenstein at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Palomar Health Downtown CampusEscondido, CA · Acute Care Hospital · CCN 050115
- Palomar Medical Center PowayPoway, CA · Acute Care Hospital · CCN 050636
Practice locations
Addresses where Joshua K. Greenstein is enrolled with Medicare (CMS data updated 2026-10-02). The first 5 of 7; the Medicare profile lists all.
- 11100 Warner Ave, Suite 218Fountain Valley, CA 92708 (714) 641‑9696
- 16466 Bernardo Ctr Dr, Suite 230San Diego, CA 92128 (858) 558‑8150
- 1955 Citracado Pkwy, Suite 301Escondido, CA 92029 (760) 294‑1660
- 320 Santa Fe Dr, Suite 212Encinitas, CA 92024 (858) 558‑8150
- 416 BroadwayChula Vista, CA 91910 (619) 427‑1144
Group practices
Medicare enrollment lists Joshua K. Greenstein as a member of this group (CMS data updated 2026-10-02).
- Balboa Nephrology Medical Group Inc76 clinicians in the group
Specialties
- Nephrologyprimary
Other nephrologists in Fountain Valley
Clinicians with the same Medicare primary specialty in Fountain Valley, CA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 1998 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1104881457 |
| 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