Dr. Thomas Leewei Chen, MD
- Medicare services, 2023
- 28
- Medicare patients, 2024
- 13
- Part D claims, 2024
- 256
- Hospital affiliations
- 3
- Industry payments
- $37
- Practice address
- 2500 Merced Street, San Leandro, CA 94577
- Practice phone
- Call (510) 454-1000
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
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Dr. Thomas Leewei Chen is an internist in San Leandro, California
Dr. Chen practices at San Leandro Medical Center in San Leandro, California, part of Kaiser Permanente.
Dr. Chen's NPI, 1699112458, was assigned on June 3, 2013. Dr. Chen graduated from Tulane University School of Medicine in 2013. Dr. Chen holds California license A133645.
- NPI
- 1699112458NPI Registry (opens in a new tab)
- Medicare PAC ID
- 8628356698
- NPI enumeration date
- June 3, 2013
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (510) 454-1000
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 39
- Medical school graduation
- 2013
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Thomas Leewei Chen practices at San Leandro Medical Center in San Leandro, California
Dr. Chen's primary practice is San Leandro Medical Center, at 2500 Merced Street, San Leandro, CA 94577 in Alameda County. The practice phone is (510) 454-1000.
- San Leandro Medical Center2500 Merced Street, San Leandro, CA 94577 · Alameda CountyPhone(510) 454-1000
Source: Dmand AI Affiliation Data
Dr. Thomas Leewei Chen is affiliated with 3 sites of care and 1 medical group
Dr. Chen's primary practice is San Leandro Medical Center in San Leandro, California, part of Kaiser Permanente. Dr. Chen is also affiliated with Alameda Health System - Highland Hospital. The medical group on file is The Permanente Medical Group, Inc. Dmand AI also links Dr. Chen to 1 more hospital, named with a free account.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Thomas Leewei Chen's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Chen practices, 3 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| San Leandro Medical Center | Available with a free account |
| +2 more affiliated sites | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Thomas Leewei Chen is one of 16,751 internists in California
Internal medicine is Dr. Chen's primary specialty in the NPI Registry, under taxonomy code 207R00000X. Dr. Chen is licensed in California.
Specialties and state licenses
- Internal medicine, CaliforniaPrimary
Internists near Dr. Chen
Counts of internists with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. Thomas Leewei Chen billed Medicare for 28 services in 2023
CMS data shows 28 Medicare services from Dr. Chen across 1 procedure code in 2023, for 13 Medicare patients. Medicare paid $1,894 for them. Every service was in a facility, such as a hospital, rather than an office.
Dr. Chen's Medicare services by type, 2018 to 2023
- 2018
- 2023
- Office and hospital visits
- 2018: 402023: 2830%
Dr. Chen compared with the California median for internists, 2023
- Dr. Chen
- California median
- Medicare services
- 28vs 36192% below
- Medicare patients
- 13vs 15191% below
- Part D claims
- 70vs 42183% below
Medians across 15,815 internists in California with Dmand AI profiles that report each measure.
Dr. Chen's most billed Medicare procedure codes, 2023
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
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Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Chen and other internists in California.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Thomas Leewei Chen treated 13 Medicare patients in 2024, average age 70
CMS counts 13 Medicare patients who saw Dr. Chen in 2024. 75% of them have high blood pressure, and 75% have high cholesterol. Their average risk score is 4.45, where 1.00 is the Medicare average, so they are sicker than most Medicare patients.
Across all payers, Dmand AI patient panel data puts Dr. Chen's median patient age at 73, with 56% women.
Chronic conditions among Dr. Chen's Medicare patients, 2024
- High blood pressure75%
- High cholesterol75%
Share of Medicare patients with each condition. A patient can have several.
Dr. Chen's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 73
Patient panel by sex, all payers
- Women56%
- Men43%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Thomas Leewei Chen wrote 256 Medicare Part D claims in 2024
In 2024, Dr. Chen wrote 256 Medicare Part D claims for 122 patients. 89% of them were for generic drugs. CMS names the drug for 70 of them, across 5 drugs with 11 or more claims each, at $800 in total drug cost. In 2023, CMS named 106 claims across 5 drugs.
Dr. Chen's Part D claims by kind of drug, 2024
- Generic229 claims89%
- Brand-name and other27 claims11%
Dr. Chen's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. Chen's Part D claims, 2024
- Opioids4%11 of 256 claims
- Antibiotics21%55 of 256 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Part D claims for drugs CMS names, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 1062024: 7034%
Drugs named by CMS: 5 in 2024, 5 in 2023.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
How Dr. Thomas Leewei Chen takes part in Medicare
Dr. Chen accepts Medicare assignment, so Medicare's approved amount is taken as full payment.
- Accepts Medicare assignment
- Yes
Source: Doctors and Clinicians National Downloadable File (CMS)
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Dr. Thomas Leewei Chen received $37 in industry payments in 2016
CMS Open Payments shows 1 general payment to Dr. Chen from 1 drug or device company in 2016. Food and beverage make up the largest share, 100% of the total. Acclarent, Inc paid the most, $37.
Companies that paid Dr. Chen the most, 2016 to 2016
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Thomas Leewei Chen graduated from Tulane University School of Medicine
Dr. Chen graduated from Tulane University School of Medicine in 2013.
- Medical school
Source: Dmand AI Professional Profile Data
Sources for Dr. Thomas Leewei Chen's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. Thomas Leewei Chen
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. Thomas Leewei Chen's NPI number?
Dr. Thomas Leewei Chen's NPI number is 1699112458. It was assigned on June 3, 2013, and it is active in the NPI Registry.
What kind of doctor is Dr. Thomas Leewei Chen?
Dr. Thomas Leewei Chen is an internist in San Leandro, California. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. Thomas Leewei Chen practice?
Dr. Chen practices at 2500 Merced Street, San Leandro, CA 94577. Dr. Chen's primary practice is San Leandro Medical Center in San Leandro, California, part of Kaiser Permanente. Dmand AI also links Dr. Chen to 1 hospital.
What is Dr. Thomas Leewei Chen's office phone number?
The practice phone on file for Dr. Chen is (510) 454-1000.
What is Dr. Thomas Leewei Chen's medical license number?
Dr. Chen holds California license A133645.
Which hospitals is Dr. Thomas Leewei Chen affiliated with?
Dr. Chen practices at San Leandro Medical Center in San Leandro, California. Dr. Chen is also affiliated with Alameda Health System - Highland Hospital. Dmand AI links Dr. Chen to 1 more hospital.
What medical group is Dr. Thomas Leewei Chen part of?
Dr. Chen is linked to The Permanente Medical Group, Inc.
Does Dr. Thomas Leewei Chen accept Medicare?
Yes. CMS data shows Dr. Chen billed Medicare for 28 services in 2023, and Dr. Chen accepts Medicare assignment.
How many Medicare patients does Dr. Thomas Leewei Chen see?
CMS counts 13 Medicare patients who saw Dr. Chen in 2024, with an average age of 70.
What services does Dr. Thomas Leewei Chen bill to Medicare?
In 2023, Dr. Chen's most billed Medicare services were hospital inpatient care (99232).
Show 4 more questionsShow fewer questions
Where did Dr. Thomas Leewei Chen go to medical school?
Dr. Chen graduated from Tulane University School of Medicine in 2013.
What drugs does Dr. Thomas Leewei Chen prescribe most?
In 2024 Medicare Part D data, Dr. Chen's most prescribed drugs by claims were Cefpodoxime Proxetil, Furosemide and Atorvastatin Calcium.
Has Dr. Thomas Leewei Chen received payments from drug or device companies?
CMS Open Payments shows $37 in general payments to Dr. Chen from 1 company from 2016 to 2016. The largest total came from Acclarent, Inc.
How long has Dr. Thomas Leewei Chen been practicing?
Dr. Chen graduated from medical school in 2013, 13 years ago.
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