Quick answers
- Does Claire T. Diep accept Medicare assignment?
- Yes. Medicare's clinician data says Claire T. Diep 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 Claire T. Diep see?
- In 2024, CMS data shows 294 Original Medicare patients and 1,950 services for Claire T. Diep. This counts Original Medicare only and measures volume, not quality.
- What is Claire T. Diep's NPI number?
- 1366508707. 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 Claire T. Diep, 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 | 294 |
|---|---|
| Services billed to Medicare | 1,950 |
| Different services or procedures | 15 |
| Participating Medicare provider | Yes |
| Average age of these patients | 76 |
Most frequent services
- Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)1,355 services
- Administration of influenza virus vaccine (G0008)181 services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)146 services
- Influenza vaccine split virus, preservative free (90662)100 services
- Influenza vaccine, inactivated (90653)74 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).
- High blood pressure75%
- High cholesterol75%
- Diabetes45%
- Osteoporosis35%
- Arthritis30%
- Chronic kidney disease23%
Hospitals where Claire T. Diep works
Medicare's Facility Affiliation Data lists Claire T. Diep at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.
- St Rose HospitalHayward, CA · Acute Care Hospital · Medicare rating: 1 of 5 stars · Emergency services: not listed by Medicare · CCN 050002
- Washington HospitalFremont, CA · Acute Care Hospital · Medicare rating: 2 of 5 stars · Emergency services: listed by Medicare · CCN 050195
Practice locations
Addresses where Claire T. Diep is enrolled with Medicare (CMS data updated October 2, 2026).
- 33509 Western AveUnion City, CA 94587 (510) 441‑8081
Specialties
- Internal Medicineprimary
Other internal medicine doctors in Union City
Clinicians with the same Medicare primary specialty in Union City, CA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Eastern Virginia Medical School |
| Graduation year | 1994 (32 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1366508707 |
| 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 October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- 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