Quick answers
- Does Karen M. Wai accept Medicare assignment?
- Yes. Medicare's clinician data says Karen M. Wai 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 Karen M. Wai see?
- In 2024, CMS data shows 318 Original Medicare patients and 1,103 services for Karen M. Wai. This counts Original Medicare only and measures volume, not quality.
- What is Karen M. Wai's NPI number?
- 1073017208. 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 Karen M. Wai, 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 | 318 |
|---|---|
| Services billed to Medicare | 1,103 |
| Different services or procedures | 30 |
| Participating Medicare provider | Yes |
| Average age of these patients | 74 |
Most frequent services
- Imaging of retina (92134)328 services
- Visit complexity inherent to evaluation and management associated with medical care services that serve as the continuing focal point for all needed health care services and/or with medical care services that are part of ongoing care related to a patient's (G2211)240 services
- Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)179 services
- New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)138 services
- Injection of drug into eye (67028)67 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%
- Diabetes49%
- Arthritis35%
- Ischemic heart disease26%
- Chronic kidney disease24%
Hospitals where Karen M. Wai works
Medicare's Facility Affiliation Data lists Karen M. Wai 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.
- Stanford Health CareStanford, CA · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 050441
Practice locations
Addresses where Karen M. Wai is enrolled with Medicare (CMS data updated October 2, 2026).
- 20642 John DrCastro Valley, CA 94546 (888) 924‑1036
- 300 Pasteur DrStanford, CA 94305 (650) 723‑4000
- 751 S Bascom AveSan Jose, CA 95128 (408) 885‑5000
- 751 S Bascom Ave, Santa Clara Vly MedSan Jose, CA 95128 (408) 885‑5000
Group practices
Medicare enrollment lists Karen M. Wai as a member of these groups (CMS data updated October 2, 2026).
- Stanford Health Care3,122 clinicians in the group
- County of Santa Clara1,022 clinicians in the group
- University Healthcare Alliance327 clinicians in the group
Specialties
- Ophthalmologyprimary
Other ophthalmologists in Castro Valley
Clinicians with the same Medicare primary specialty in Castro Valley, CA — not a recommendation.
Other clinicians in Stanford Health Care
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 2018 (8 years since medical school) |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1073017208 |
| 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