John Michael Gansner, M.D./PH.D.
Hematology (Internal Medicine) Physician · Boston, MA
John Michael Gansner, M.D./PH.D. is a hematology (internal medicine) physician with a practice address in Boston, Massachusetts, and NPI 1952621831, issued on Jun 2, 2010. Check the license (Massachusetts 265408, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- John Michael Gansner
- Credential
- M.D./PH.D.
- Primary taxonomy
- Hematology (Internal Medicine) Physician 207RH0000X
- License numbers
- 265408 MA
244635 MA
Self-reported in NPPES; status is on the state search - Practice location
- 450 Brookline Ave, Boston, MA 02215
- Phone
- (617) 632-3779
- Enumerated
- Jun 2, 2010
- Record last updated
- May 31, 2016 (not updated in 10 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20160706000305); accepts Medicare assignment
- Medical or professional school
- Washington University School Of Medicine, 2010
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest hematology (internal medicine) physician records → All 117 in Massachusetts → Look up another NPI →
Also registered at 450 Brookline Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Gregory Abel, MDHematology & Oncology Physician1285611954
- Lara Abousamra, PHARMDPharmacist Clinician (PhC)/ Clinical Pharmacy Specialist1851183404
- Karley Adams, PAPhysician Assistant1578261764
- Lauren Adams, PA-CPhysician Assistant1902763469
- Ana Aguilar-Bonilla, M.D.Pediatric Hematology & Oncology Physician1023319761
- Andrew Aguirre, MD, PHDMedical Oncology Physician1609071208
Verify John Michael Gansner in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
Search for license 265408Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
96% fewer Medicare Part D claims than the average hematology (internal medicine) physician in 2024
21 Medicare Part D claims, against an average of 496 among the 1,036 providers of this specialty who prescribed in Part D. Brand-name drugs were 0% of claims.
Most prescribed
- Hydroxyurea19 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 2 group practices
- Brigham And Womens Physicians Organization IncBoston, MA
- Dana-Farber Cancer Institute, Inc.Boston, MA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
John Michael Gansner among 117 hematology (internal medicine) physician records in Massachusetts
John Michael Gansner, M.D./PH.D. is one of 117 hematology (internal medicine) physician records with a practice address in Massachusetts. 77% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2010, is newer than 62% of them.
- NPI issued2010 · 62% of these records are older, 36% newer
- In a Medicare fileYes · 77% of these records are
- In the CMS Doctors and Clinicians fileYes · 66% of these records are
- Graduated2010 · median 2006 among the 77 with a school on file
- Record last updated2016 · 43% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RH0000X and a Massachusetts practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Hematology (Internal Medicine) Physician providers in Massachusetts
There are 117 hematology (internal medicine) physician records in Massachusetts.
All 117 in Massachusetts → Every provider in Boston → Hematology (Internal Medicine) Physician nationwide →
The 8 hematology (internal medicine) physician records with the nearest ZIP codes
- Joseph Antin, MDBoston, MA 022151861469249
- Nancy Berliner, MDBoston, MA 022151609855576
- Jorge Castillo, MDBoston, MA 022151689891129
- Joan Goldberg, MDBoston, MA 022151568558039
- Monique Hartley-Brown, M.D.Boston, MA 022151992904387
- Robin Marie Joyce, M.D.Boston, MA 022151659318350
- John Koreth, MBBS DPHILBoston, MA 022151396706503
- James Levine, M.D.Boston, MA 022151275573701
Common questions
What is John Michael Gansner, M.D./PH.D.'s NPI number?
John Michael Gansner, M.D./PH.D.'s National Provider Identifier (NPI) is 1952621831, issued on Jun 2, 2010. An NPI identifies a provider in billing; it is not a license.
Where is John Michael Gansner, M.D./PH.D. located?
The NPPES record lists a practice address at 450 Brookline Ave, Boston, MA, 02215. Phone: (617) 632-3779. Providers update this record themselves, so call before visiting.
How can I verify John Michael Gansner, M.D./PH.D.'s license?
NPPES lists Massachusetts license number 265408, 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 John Michael Gansner, M.D./PH.D. prescribe under Medicare Part D?
In 2024, John Michael Gansner, M.D./PH.D. had 21 Medicare Part D claims; the average among hematology (internal medicine) physician prescribers was 496. 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.