Quick answers
- Does John P. Gruen accept Medicare assignment?
- Yes. Medicare's clinician data says John P. Gruen accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- What is John P. Gruen's NPI number?
- 1194769570. 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 P. Gruen is enrolled with Medicare (CMS data updated October 2, 2026). The first 5 of 6; the Medicare profile lists all.
- 1500 San Pablo StLos Angeles, CA 90033
- 1516 San Pablo StLos Angeles, CA 90033 (800) 872‑2273
- 1516 San Pablo St, Suite L3100Los Angeles, CA 90033 (800) 872‑2273
- 1520 San Pablo StLos Angeles, CA 90033 (800) 872‑2273
- 1520 San Pablo St, Fl 4Los Angeles, CA 90033 (800) 872‑2273
Group practices
Medicare enrollment lists John P. Gruen as a member of this group (CMS data updated October 2, 2026).
- USC Care Medical Group Inc1,380 clinicians in the group
Specialties
- Neurosurgeryprimary
Other neurosurgeons in Los Angeles
Clinicians with the same Medicare primary specialty in Los Angeles, CA — not a recommendation.
Other clinicians in USC Care Medical Group Inc
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Columbia University College Of Physicians And Surgeons |
| Graduation year | 1986 (40 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1194769570 |
| 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 October 2, 2026, retrieved October 29, 2026
- 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