Quick answers
- Does John W. Fenton accept Medicare assignment?
- Yes. Medicare's clinician data says John W. Fenton 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.
- How many Medicare patients does John W. Fenton see?
- In 2024, CMS data shows 68 Original Medicare patients and 547 services for John W. Fenton. This counts Original Medicare only and measures volume, not quality.
- What is John W. Fenton's NPI number?
- 1154478550. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Medicare activity in 2024
Official CMS public-use data for John W. Fenton, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.
| Original Medicare patients | 68 |
|---|---|
| Services billed to Medicare | 547 |
| Different services or procedures | 7 |
| Participating Medicare provider | Yes |
| Average age of these patients | 49 |
Most frequent services
- Subsequent hospital care with straightforward or low level of medical decision making, per day, if using time, at least 25 minutes (99231)455 services
- Initial hospital care with straightforward or low level of medical decision making, per day, if using time, at least 40 minutes (99221)35 services
- Hospital discharge day management, 30 minutes or less (99238)29 services
- Hospital discharge day management, more than 30 minutes (99239)17 services
Chronic conditions among these patients
Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).
- Anxiety75%
- High blood pressure50%
- High cholesterol46%
- Depression44%
- Diabetes31%
- Asthma28%
Practice locations
Addresses where John W. Fenton is enrolled with Medicare (CMS data updated October 2, 2026).
- 15400 Foothill BlvdCastro Valley, CA 94578 (510) 895‑4200
Group practices
Medicare enrollment lists John W. Fenton as a member of this group (CMS data updated October 2, 2026).
- Alameda Health System601 clinicians in the group
Specialties
- Psychiatryprimary
Other psychiatrists in Castro Valley
Clinicians with the same Medicare primary specialty in Castro Valley, CA — not a recommendation.
Other clinicians in Alameda Health System
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 2002 (24 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1154478550 |
| 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
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- 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