Timothy S. Loo, M.D.
Internal Medicine Physician · Boston, MA
Timothy S. Loo, M.D. is an internal medicine physician with a practice address in Boston, Massachusetts, and NPI 1871584813, issued on Oct 31, 2005. Check the license (Massachusetts 215918, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- Timothy S. Loo
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 215918 MA
Self-reported in NPPES; status is on the state search - Practice location
- 330 Brookline Ave, Boston, MA 02215
- Phone
- (617) 667-9600
- Enumerated
- Oct 31, 2005
- Record last updated
- Sep 6, 2007 (not updated in 19 years: call before relying on the address or phone)
- Fax
- (617) 667-8665
- Medicaid ID
- 0180301 MA
- Medicare enrollment
- Enrolled (PECOS I20080703000464); accepts Medicare assignment
- Medical or professional school
- Johns Hopkins University School Of Medicine, 1994
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 6,825 in Massachusetts → Look up another NPI →
Also registered at 330 Brookline Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Timothy S. Loo in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
Search for license 215918Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
51% more Medicare Part D claims than the average internal medicine physician in 2024
4,791 Medicare Part D claims for 436 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 11% of claims. 130 claims were for opioids.
Most prescribed
- Atorvastatin Calcium393 claims
- Amlodipine Besylate321 claims
- Omeprazole174 claims
- Metoprolol Succinate149 claims
- Losartan Potassium144 claims
- Lisinopril140 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.
Bills Medicare through one group practice
- Harvard Medical Faculty Phys AT Beth Israel Deaconess Med Ctr IncBoston, MA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Timothy S. Loo among 6,825 internal medicine physician records in Massachusetts
Timothy S. Loo, M.D. is one of 6,825 internal medicine physician records with a practice address in Massachusetts. 75% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2005, is newer than 0% of them.
- NPI issued2005 · 0% of these records are older, 88% newer
- In a Medicare fileYes · 75% of these records are
- In the CMS Doctors and Clinicians fileYes · 60% of these records are
- Graduated1994 · median 2004 among the 4,103 with a school on file
- Record last updated2007 · 64% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a Massachusetts practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
2,320 internal medicine physician records list a practice address in Boston
They are 2,320 of the 41,865 NPPES records with a practice address in Boston, and 6,825 internal medicine physician records in Massachusetts.
All 6,825 in Massachusetts → Every provider in Boston → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Stephen Boswell, M.D.Boston, MA 022151477541217
- Jennifer Cluett, MDBoston, MA 022151962491183
- Jan Cook, M.D.Boston, MA 022151437152139
- Rachel Freedman, M.D.Boston, MA 022151942297189
- Joseph Gesmundo, MDBoston, MA 022151891785069
- Alex Gonzalez, MD, MPHBoston, MA 022151134101629
- Scott Harris, MDBoston, MA 022151871581694
- Joseph Li, M.D.Boston, MA 022151043209380
Common questions
What is Timothy S. Loo, M.D.'s NPI number?
Timothy S. Loo, M.D.'s National Provider Identifier (NPI) is 1871584813, issued on Oct 31, 2005. An NPI identifies a provider in billing; it is not a license.
Where is Timothy S. Loo, M.D. located?
The NPPES record lists a practice address at 330 Brookline Ave, Boston, MA, 02215. Phone: (617) 667-9600. Providers update this record themselves, so call before visiting.
How can I verify Timothy S. Loo, M.D.'s license?
NPPES lists Massachusetts license number 215918, as entered by the provider. Search the Massachusetts Board of Registration in Medicine at https://findmydoctor.mass.gov/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Timothy S. Loo, M.D. prescribe under Medicare Part D?
In 2024, Timothy S. Loo, M.D. had 4,791 Medicare Part D claims for 436 beneficiaries; the average among internal medicine physician prescribers was 3,176. 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.