Louis T. Chau, M.D.
Emergency Medicine Physician · Corona, CA
Louis T. Chau, M.D. is an emergency medicine physician with a practice address in Corona, California, and NPI 1225144918, issued on Aug 22, 2006. Check the license (California A64423, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Louis T. Chau
- Credential
- M.D.
- Primary taxonomy
- Emergency Medicine Physician 207P00000X
- License number
- A64423 CA
Self-reported in NPPES; status is on the state search - Practice location
- 800 S Main St, Corona, CA 92882
- Phone
- (909) 736-6241
- Enumerated
- Aug 22, 2006
- Record last updated
- Dec 3, 2021 (not updated in 5 years: call before relying on the address or phone)
- Fax
- (909) 736-6283
- Medicaid ID
- 00A644230 CA
- Entity
- Type 1 · individual
8 nearest emergency medicine physician records → All 7,751 in California → Look up another NPI →
Also registered at 800 S Main St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Charles Addo-Yobo, DOEmergency Medicine Physician1821625955
- James Ahn, M.D.Anesthesiology Physician1588641963
- Julie Ahn, PA-CPhysician Assistant1346802543
- Thomas Assali, DOInternal Medicine Physician1598225062
- Cynthia Bailey, P.A.-CPhysician Assistant1316053036
- David Bear, M.D.Emergency Medicine Physician1114033883
Verify Louis T. Chau in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A64423Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
44% fewer Medicare Part D claims than the average emergency medicine physician in 2024
126 Medicare Part D claims for 101 beneficiaries, against an average of 226 among the 54,106 providers of this specialty who prescribed in Part D. Brand-name drugs were 11% of claims. 14 claims were for opioids.
Most prescribed
- Cephalexin25 claims
- Prednisone13 claims
- Hydrocodone-Acetaminophen12 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.
Louis T. Chau among 7,751 emergency medicine physician records in California
Louis T. Chau, M.D. 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 2006, is newer than 4% of them.
- NPI issued2006 · 4% of these records are older, 60% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileNo · 59% of these records are
- Record last updated2021 · 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).
Emergency Medicine Physician providers in California
There are 7,751 emergency medicine physician records in California.
All 7,751 in California → Every provider in Corona → Emergency Medicine Physician nationwide →
The 8 emergency medicine physician records with the nearest ZIP codes
- Charles Addo-Yobo, DOCorona, CA 928821821625955
- David Bear, M.D.Corona, CA 928821114033883
- Neil Bhutwala, DOCorona, CA 928821316500408
- James Boyd, M.D.Corona, CA 928821184730855
- Joaquin Castillo Marroquin, DOCorona, CA 928821316407323
- Nancy Chung, MDCorona, CA 928821275577447
- Tam Dang, M.D.Corona, CA 928821275824799
- Aakanksha Fenster, M.D.Corona, CA 928821659661163
Common questions
What is Louis T. Chau, M.D.'s NPI number?
Louis T. Chau, M.D.'s National Provider Identifier (NPI) is 1225144918, issued on Aug 22, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Louis T. Chau, M.D. located?
The NPPES record lists a practice address at 800 S Main St, Corona, CA, 92882. Phone: (909) 736-6241. Providers update this record themselves, so call before visiting.
How can I verify Louis T. Chau, M.D.'s license?
NPPES lists California license number A64423, 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 Louis T. Chau, M.D. prescribe under Medicare Part D?
In 2024, Louis T. Chau, M.D. had 126 Medicare Part D claims for 101 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.