Winnie W. Chan, MD
Emergency Medicine Physician · Castro Valley, CA
Winnie W. Chan, MD is an emergency medicine physician with a practice address in Castro Valley, California, and NPI 1538521281, issued on Mar 22, 2016. Check the license (California A152574, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Winnie W. Chan
- Credential
- MD
- Primary taxonomy
- Emergency Medicine Physician 207P00000X
- License number
- A152574 CA
Self-reported in NPPES; status is on the state search - Practice location
- 20103 Lake Chabot RD, Castro Valley, CA 94546
- Phone
- (877) 346-2211
- Enumerated
- Mar 22, 2016
- Record last updated
- May 31, 2022
- Fax
- (626) 623-1227
- Medicare enrollment
- Enrolled (PECOS I20200615003672); accepts Medicare assignment
- Medical or professional school
- University Of California, San Francisco School Of Medicine, 2016
- Entity
- Type 1 · individual
8 nearest emergency medicine physician records → All 7,751 in California → Look up another NPI →
Also registered at 20103 Lake Chabot RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Alexei AdanEmergency Medicine Physician1679968978
- Maria Ait Rais, M.D.Hospitalist Physician1811239304
- Latricia Amadeo, RNRegistered Nurse1003407115
- Sandhya Ashokkumar, MDCritical Care Medicine (Internal Medicine) Physician1457913402
- Oluwaseyi Balasire, M.D.Hospitalist Physician1003235243
- Rachna Bali, DOHospitalist Physician1346541554
Verify Winnie W. Chan in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A152574Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
1% more Medicare Part D claims than the average emergency medicine physician in 2024
228 Medicare Part D claims for 132 beneficiaries, against an average of 226 among the 54,106 providers of this specialty who prescribed in Part D. Brand-name drugs were 12% of claims. 18 claims were for opioids.
Most prescribed
- Oxycodone Hcl12 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Bills Medicare through 2 group practices
- Eden Emergency Medical Group IncCastro Valley, CA
- Permanente Medical Group IncSan Jose, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Winnie W. Chan among 7,751 emergency medicine physician records in California
Winnie W. Chan, MD is one of 7,751 emergency medicine physician records with a practice address in California. 81% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2016, is newer than 75% of them.
- NPI issued2016 · 75% of these records are older, 22% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileYes · 59% of these records are
- Graduated2016 · median 2011 among the 4,560 with a school on file
- Record last updated2022 · 59% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207P00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
20 emergency medicine physician records list a practice address in Castro Valley
They are 20 of the 999 NPPES records with a practice address in Castro Valley, and 7,751 emergency medicine physician records in California.
All 7,751 in California → Every provider in Castro Valley → Emergency Medicine Physician nationwide →
The 8 emergency medicine physician records with the nearest ZIP codes
- Alexei AdanCastro Valley, CA 945461679968978
- Merrill Chandler, MDCastro Valley, CA 945461508847237
- Nathalie Coeller, MDCastro Valley, CA 945461265607402
- Ralph Damato, MDCastro Valley, CA 945461225014673
- Rochelle Eggleston Philapil, MDCastro Valley, CA 945461265423610
- Alan Gottlieb, MDCastro Valley, CA 945461306837521
- Peter Joseph, MDCastro Valley, CA 945461396729158
- Tatiana Mamantov, MDCastro Valley, CA 945461629069059
Common questions
What is Winnie W. Chan, MD's NPI number?
Winnie W. Chan, MD's National Provider Identifier (NPI) is 1538521281, issued on Mar 22, 2016. An NPI identifies a provider in billing; it is not a license.
Where is Winnie W. Chan, MD located?
The NPPES record lists a practice address at 20103 Lake Chabot RD, Castro Valley, CA, 94546. Phone: (877) 346-2211. Providers update this record themselves, so call before visiting.
How can I verify Winnie W. Chan, MD's license?
NPPES lists California license number A152574, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Winnie W. Chan, MD prescribe under Medicare Part D?
In 2024, Winnie W. Chan, MD had 228 Medicare Part D claims for 132 beneficiaries; the average among emergency medicine physician prescribers was 226. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.