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Dr. Thomas J. Chen, MD
NPI1053329227PAC ID8224032347
- Part D claims, 2024
- 1,920
- Publications
- 3
- Hospital affiliations
- 1
- Industry payments
- $1,142
- Medical group
- 1
- Practice address
- 9961 Sierra Ave, Fontana, CA 92335
- Practice phone
- Call (909) 427-5000
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. Chen's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. Thomas J. Chen is an internist in Fontana, California
Dr. Chen practices at Fontana Medical Center in Fontana, California, part of Kaiser Permanente.
Dr. Chen's NPI, 1053329227, was assigned on August 4, 2006. Dr. Chen graduated from Loma Linda University School Of Medicine in 2002. Dr. Chen holds California license A85898.
NPI and contact details
- NPI
- 1053329227NPI Registry (opens in a new tab)
- Medicare PAC ID
- 8224032347
- NPI enumeration date
- August 4, 2006
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (909) 427-5000
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 50
- Medical school graduation
- 2002
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Thomas J. Chen practices at Fontana Medical Center in Fontana, California
Dr. Chen's primary practice is Fontana Medical Center, at 9961 Sierra Ave, Fontana, CA 92335 in San Bernardino County. The practice phone is (909) 427-5000.
- Fontana Medical Center9961 Sierra Ave, Fontana, CA 92335 · San Bernardino CountyPhone(909) 427-5000
Source: Dmand AI Affiliation Data
Dr. Thomas J. Chen is affiliated with 2 sites of care and 1 medical group
Dr. Chen's primary practice is Fontana Medical Center in Fontana, California, part of Kaiser Permanente. The medical group on file is Southern California Permanente Medical Group. Dmand AI also links Dr. Chen to 1 more group practice or clinic, 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 J. Chen's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Chen practices, 2 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Fontana Medical Center | Available with a free account |
| +1 more affiliated site | Available with a free account |
Source: Dmand AI Technology Install Data
For health IT teams
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Dr. Thomas J. 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 board certified in internal medicine by the American Board of Internal Medicine. 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 J. Chen's patients have a median age of 53
Across all payers, Dmand AI patient panel data puts Dr. Chen's median patient age at 53, with 53% women.
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 53
Patient panel by sex, all payers
- Women53%
- Men46%
Source: Dmand AI Patient Panel Data
Dr. Thomas J. Chen wrote 1,920 Medicare Part D claims in 2024
In 2024, Dr. Chen wrote 1,920 Medicare Part D claims for 196 patients. 86% of them were for generic drugs. CMS names the drug for 1,471 of them, across 47 drugs with 11 or more claims each, at $69,639 in total drug cost. In 2023, CMS named 1,205 claims across 40 drugs.
Part D claims, 20241,920
Drugs named by CMS47
Total drug cost$69,639
Part D patients196
Dr. Chen's Part D claims by kind of drug, 2024
- Generic1,646 claims86%
- Brand-name232 claims12%
- Other42 claims2%
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
- Opioids5%88 of 1,920 claims
- Antibiotics2%37 of 1,920 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: 1,2052024: 1,47122%
Drugs named by CMS: 47 in 2024, 40 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 J. 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 J. Chen has 3 publications on record
Dmand AI links 3 papers to Dr. Chen. The most frequent topics are Air Pollutants, Air Pollution and Polycyclic Aromatic Hydrocarbons.
Papers3
Topics Dr. Chen writes about most
- Air Pollutants
- Air Pollution
- Polycyclic Aromatic Hydrocarbons
Recent publications by Dr. Chen
Emissions of polycyclic aromatic hydrocarbons from batch hot mix asphalt plants (opens in a new tab)
Environ Sci Technol
Air PollutantsAir PollutionCarbon
CarcinogensData Interpretation, StatisticalDrug Interactions
See who Dr. Chen researches with
Physician Network Discovery turns co-authorship, shared hospitals and shared groups into a map of who Dr. Chen works with, so you can find a warm path to the right internists.
Sources: PubMed (National Library of Medicine); and Dmand AI Research Linkage
Dr. Thomas J. Chen received $1,142 in industry payments from 2017 to 2025
CMS Open Payments shows 12 general payments to Dr. Chen from 11 drug and device companies from 2017 to 2025. Food and beverage make up the largest share, 100% of the total. Bristol-Myers Squibb Company paid the most, $193.
General payments to Dr. Chen by program year, 2017 to 2025
Companies that paid Dr. Chen the most, 2017 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Thomas J. Chen has 1 award and honors on record
Dmand AI lists 1 award for Dr. Chen, most recently CMS Stage 1 EHR in 2013.
Awards and honors for Dr. Chen
- 2013
- CMS Stage 1 EHR
Source: Dmand AI Professional Profile Data
Dr. Thomas J. Chen graduated from Loma Linda University School Of Medicine
Dr. Chen graduated from Loma Linda University School Of Medicine in 2002.
- Medical school
- Board certified in internal medicine
Source: Dmand AI Professional Profile Data
Dr. Thomas J. Chen accepts plans from 9 insurance carriers
Dr. Chen is in network with 9 carriers, including United Healthcare, Kaiser Permanente and Blue Cross Blue Shield of Michigan. Medicare plans come from the most carriers, 5. Check the plan with the practice before a visit.
- United Healthcare
- Kaiser Permanente
- Blue Cross Blue Shield of Michigan
- HCSC
- Regence Health Plans
- Aspirus Health Plan
- Blue Cross and Blue Shield of Kansas City
- CMS Medicare
- +1 more carriersWith a free account
Plan types Dr. Chen accepts, by number of carriers
- Medicare5
- PPO5
- POS3
- EPO2
- HMO2
Source: Dmand AI Insurance Network Data
Sources for Dr. Thomas J. 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 patients and the all-payer patient panel | Dmand AI Patient Panel Data |
| 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) |
| Publications, topics and co-authors | PubMed (National Library of Medicine) (opens in a new tab)Dmand AI Research Linkage |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Awards and committee roles | Dmand AI Professional Profile Data |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| Insurance carriers and plan types | Dmand AI Insurance Network 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 J. 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 J. Chen's NPI number?
Dr. Thomas J. Chen's NPI number is 1053329227. It was assigned on August 4, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Thomas J. Chen?
Dr. Thomas J. Chen is an internist in Fontana, California. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. Thomas J. Chen practice?
Dr. Chen practices at 9961 Sierra Ave, Fontana, CA 92335. Dr. Chen's primary practice is Fontana Medical Center in Fontana, California, part of Kaiser Permanente. Dmand AI also links Dr. Chen to 1 group practice or clinic.
What is Dr. Thomas J. Chen's office phone number?
The practice phone on file for Dr. Chen is (909) 427-5000.
What is Dr. Thomas J. Chen's medical license number?
Dr. Chen holds California license A85898.
Which hospitals is Dr. Thomas J. Chen affiliated with?
Dr. Chen practices at Fontana Medical Center in Fontana, California.
What medical group is Dr. Thomas J. Chen part of?
Dr. Chen is linked to Southern California Permanente Medical Group.
Does Dr. Thomas J. Chen accept Medicare?
Yes. CMS lists Dr. Chen as accepting Medicare assignment.
Is Dr. Thomas J. Chen board certified?
Yes. Dr. Chen is board certified in internal medicine by the American Board of Internal Medicine.
Where did Dr. Thomas J. Chen go to medical school?
Dr. Chen graduated from Loma Linda University School Of Medicine in 2002.
Show 5 more questionsShow fewer questions
What drugs does Dr. Thomas J. Chen prescribe most?
In 2024 Medicare Part D data, Dr. Chen's most prescribed drugs by claims were Atorvastatin Calcium, Losartan Potassium and Amlodipine Besylate.
Has Dr. Thomas J. Chen received payments from drug or device companies?
CMS Open Payments shows $1,142 in general payments to Dr. Chen from 11 companies from 2017 to 2025. The largest total came from Bristol-Myers Squibb Company.
How long has Dr. Thomas J. Chen been practicing?
Dr. Chen graduated from medical school in 2002, 24 years ago.
Does Dr. Thomas J. Chen do research?
Dmand AI links 3 publications to Dr. Chen.
What insurance does Dr. Thomas J. Chen accept?
Dr. Chen is in network with 9 carriers, including United Healthcare, Kaiser Permanente and Blue Cross Blue Shield of Michigan. Medicare plans come from the most carriers, 5. Check the plan with the practice before a visit.
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