Dr. Thomas Claudio Guillermo Tsai, MD
- Part D claims, 2024
- 257
- Industry payments
- $330
- State license
- 1
- Year NPI issued
- 2023
- Practice address
- 115 Lincoln St, Framingham, MA 01702
- Practice phone
- Call (508) 383-1572
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Metrowest Medical Center - Framingham Union Hospital
Framingham, Massachusetts
Find Dr. Tsai'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 Claudio Guillermo Tsai is an internist in Framingham, Massachusetts
Dr. Tsai practices at Metrowest Medical Center - Framingham Union Hospital in Framingham, Massachusetts.
Dr. Tsai's NPI, 1548963945, was assigned on March 24, 2023. Dr. Tsai holds Massachusetts license 3014722.
- NPI
- 1548963945NPI Registry (opens in a new tab)
- NPI enumeration date
- March 24, 2023
- NPI status
- Active
- Practice phone
- (508) 383-1572
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Practice Data
Dr. Thomas Claudio Guillermo Tsai practices at Metrowest Medical Center - Framingham Union Hospital in Framingham, Massachusetts
Dr. Tsai's primary practice is Metrowest Medical Center - Framingham Union Hospital, at 115 Lincoln St, Framingham, MA 01702 in Middlesex County. The practice phone is (508) 383-1572.
- Metrowest Medical Center - Framingham Union Hospital115 Lincoln St, Framingham, MA 01702 · Middlesex CountyPhone(508) 383-1572
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Dr. Thomas Claudio Guillermo Tsai is affiliated with 1 site of care
Dr. Tsai's primary practice is Metrowest Medical Center - Framingham Union Hospital in Framingham, Massachusetts.
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Dmand AI tracks the EHR system at Dr. Thomas Claudio Guillermo Tsai's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Tsai practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Metrowest Medical Center - Framingham Union Hospital | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Thomas Claudio Guillermo Tsai is one of 5,528 internists in Massachusetts
Internal medicine is Dr. Tsai's primary specialty in the NPI Registry, under taxonomy code 207R00000X. Dr. Tsai is licensed in Massachusetts.
Specialties and state licenses
- Internal medicine, MassachusettsPrimary
Internists near Dr. Tsai
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 Claudio Guillermo Tsai's patients have a median age of 75
Across all payers, Dmand AI patient panel data puts Dr. Tsai's median patient age at 75, with 63% women.
Dr. Tsai's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 75
Patient panel by sex, all payers
- Women63%
- Men38%
Source: Dmand AI Patient Panel Data
Dr. Thomas Claudio Guillermo Tsai wrote 257 Medicare Part D claims in 2024
In 2024, Dr. Tsai wrote 257 Medicare Part D claims for 64 patients. 81% of them were for generic drugs. CMS names the drug for 48 of them, across 4 drugs with 11 or more claims each, at $11,920 in total drug cost.
Dr. Tsai's Part D claims by kind of drug, 2024
- Generic207 claims81%
- Brand-name50 claims19%
Dr. Tsai'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.
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
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Dr. Thomas Claudio Guillermo Tsai received $330 in industry payments from 2023 to 2025
CMS Open Payments shows 8 general payments to Dr. Tsai from 4 drug and device companies from 2023 to 2025. Food and beverage make up the largest share, 100% of the total. Janssen Pharmaceuticals, Inc paid the most, $117.
General payments to Dr. Tsai by program year, 2023 to 2025
Companies that paid Dr. Tsai the most, 2023 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Sources for Dr. Thomas Claudio Guillermo Tsai'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 | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice Data |
| Primary practice, affiliations and health system | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice 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) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| 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 Claudio Guillermo Tsai
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 Claudio Guillermo Tsai's NPI number?
Dr. Thomas Claudio Guillermo Tsai's NPI number is 1548963945. It was assigned on March 24, 2023, and it is active in the NPI Registry.
What kind of doctor is Dr. Thomas Claudio Guillermo Tsai?
Dr. Thomas Claudio Guillermo Tsai is an internist in Framingham, Massachusetts. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. Thomas Claudio Guillermo Tsai practice?
Dr. Tsai practices at 115 Lincoln St, Framingham, MA 01702. Dr. Tsai's primary practice is Metrowest Medical Center - Framingham Union Hospital in Framingham, Massachusetts.
What is Dr. Thomas Claudio Guillermo Tsai's office phone number?
The practice phone on file for Dr. Tsai is (508) 383-1572.
What is Dr. Thomas Claudio Guillermo Tsai's medical license number?
Dr. Tsai holds Massachusetts license 3014722.
What drugs does Dr. Thomas Claudio Guillermo Tsai prescribe most?
In 2024 Medicare Part D data, Dr. Tsai's most prescribed drugs by claims were Atenolol, Atorvastatin Calcium and Mounjaro.
Has Dr. Thomas Claudio Guillermo Tsai received payments from drug or device companies?
CMS Open Payments shows $330 in general payments to Dr. Tsai from 4 companies from 2023 to 2025. The largest total came from Janssen Pharmaceuticals, Inc.
How long has Dr. Thomas Claudio Guillermo Tsai been practicing?
Dr. Tsai's NPI was assigned in 2023.
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