Cynthia Chyn Tsui, MD
Nephrology Physician · Fremont, CA
Cynthia Chyn Tsui, MD is a nephrology physician with a practice address in Fremont, California, and NPI 1942476940, issued on Apr 30, 2008. Check the license (California C138840, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Cynthia Chyn Tsui
- Credential
- MD
- Primary taxonomy
- Nephrology Physician 207RN0300X
- License number
- C138840 CA
Self-reported in NPPES; status is on the state search - Practice location
- 39370 Mozart Ter Unit 106, Fremont, CA 94538
- Phone
- (510) 925-2126
- Enumerated
- Apr 30, 2008
- Record last updated
- Nov 27, 2023
- Fax
- (510) 925-4260
- Medicare enrollment
- Enrolled (PECOS I20160330000666); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest nephrology physician records → All 1,468 in California → Look up another NPI →
Verify Cynthia Chyn Tsui in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license C138840Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
95% fewer Medicare Part D claims than the average nephrology physician in 2024
73 Medicare Part D claims, against an average of 1,465 among the 10,986 providers of this specialty who prescribed in Part D. Brand-name drugs were 45% of claims.
Most prescribed
- Prosol31 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.
Industry payments in 2024: $24.58
1 payment: food and beverage; the largest payer was Neurocrine Biosciences, Inc. The 8,230 providers of this specialty with any payment received $3,091.37 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Cynthia Chyn Tsui among 1,468 nephrology physician records in California
Cynthia Chyn Tsui, MD is one of 1,468 nephrology physician records with a practice address in California. 88% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2008, is newer than 65% of them.
- NPI issued2008 · 65% of these records are older, 30% newer
- In a Medicare fileYes · 88% of these records are
- In the CMS Doctors and Clinicians fileYes · 77% of these records are
- Graduated2000 · median 2001 among the 1,128 with a school on file
- Record last updated2023 · 62% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RN0300X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Nephrology Physician providers in California
There are 1,468 nephrology physician records in California.
All 1,468 in California → Every provider in Fremont → Nephrology Physician nationwide →
The 8 nephrology physician records with the nearest ZIP codes
- Jeanie Ahn, M.D.Fremont, CA 945381053359356
- Neiha Arora, MDFremont, CA 945381588879217
- Varun ChawlaFremont, CA 945381609067537
- Qi Che, M.D.Fremont, CA 945381447429212
- Rajesh Davda, MDFremont, CA 945381740220433
- Peter Lunny, M.D.Fremont, CA 945381689621765
- Mary Palathumpat, MDFremont, CA 945381225113988
- Shalini Sundar, M.D.Fremont, CA 945381780607838
Common questions
What is Cynthia Chyn Tsui, MD's NPI number?
Cynthia Chyn Tsui, MD's National Provider Identifier (NPI) is 1942476940, issued on Apr 30, 2008. An NPI identifies a provider in billing; it is not a license.
Where is Cynthia Chyn Tsui, MD located?
The NPPES record lists a practice address at 39370 Mozart Ter Unit 106, Fremont, CA, 94538. Phone: (510) 925-2126. Providers update this record themselves, so call before visiting.
How can I verify Cynthia Chyn Tsui, MD's license?
NPPES lists California license number C138840, 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 Cynthia Chyn Tsui, MD prescribe under Medicare Part D?
In 2024, Cynthia Chyn Tsui, MD had 73 Medicare Part D claims; the average among nephrology physician prescribers was 1,465. 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.