John Ross Clark
Hematology & Oncology Physician · Boston, MA
John Ross Clark is a hematology & oncology physician with a practice address in Boston, Massachusetts, and NPI 1871550244, issued on Apr 28, 2006. Check the license (Massachusetts 49154, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- John Ross Clark
- Primary taxonomy
- Hematology & Oncology Physician 207RH0003X
- License number
- 49154 MA
Self-reported in NPPES; status is on the state search - Practice location
- 55 Fruit Street, Boston, MA 02114
- Phone
- (617) 724-4000
- Enumerated
- Apr 28, 2006
- Record last updated
- Jan 16, 2013 (not updated in 13 years: call before relying on the address or phone)
- Fax
- (617) 643-1915
- Medicaid ID
- 6194613 MA
- Entity
- Type 1 · individual
8 nearest hematology & oncology physician records → All 461 in Massachusetts → Look up another NPI →
Also registered at 55 Fruit Street
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Stephen Abraham, M.D.Specialist1487743316
- Nadia Ahmad, M.D.Internal Medicine Physician1912198037
- Fayaz Ahmed, MDStudent in an Organized Health Care Education/Training Program1528245024
- John Albin, MD, PHDInfectious Disease Physician1528472644
- Mary Amatangelo, NPAcute Care Nurse Practitioner1114191442
- Tian You An, M.D.Anesthesiology Physician1801145792
Verify John Ross Clark in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
Search for license 49154Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
94% fewer Medicare Part D claims than the average hematology & oncology physician in 2024
54 Medicare Part D claims for 13 beneficiaries, against an average of 877 among the 10,784 providers of this specialty who prescribed in Part D. Brand-name drugs were 33% of 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.
Industry payments in 2024: $18.72
1 payment: food and beverage; the largest payer was Abbott Laboratories. The 8,560 providers of this specialty with any payment received $7,481.41 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
John Ross Clark among 461 hematology & oncology physician records in Massachusetts
John Ross Clark is one of 461 hematology & oncology 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 2006, is newer than 14% of them.
- NPI issued2006 · 14% of these records are older, 50% newer
- In a Medicare fileYes · 75% of these records are
- In the CMS Doctors and Clinicians fileNo · 66% of these records are
- Record last updated2013 · 62% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RH0003X and a Massachusetts practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Hematology & Oncology Physician providers in Massachusetts
There are 461 hematology & oncology physician records in Massachusetts.
All 461 in Massachusetts → Every provider in Boston → Hematology & Oncology Physician nationwide →
The 8 hematology & oncology physician records with the nearest ZIP codes
- Vassiliki Boussiotis, MD PHDBoston, MA 021141861474215
- Marcia Browne, MDBoston, MA 021141639146210
- George Canellos, MDBoston, MA 021141114908027
- Yi-Bin Chen, MDBoston, MA 021141356332639
- Lauren Dias, MDBoston, MA 021141215928346
- Kira Gritsman, MDBoston, MA 021141174598148
- David HarmonBoston, MA 021141851358352
- Beverly Moy, MDBoston, MA 021141932199106
Common questions
What is John Ross Clark's NPI number?
John Ross Clark's National Provider Identifier (NPI) is 1871550244, issued on Apr 28, 2006. An NPI identifies a provider in billing; it is not a license.
Where is John Ross Clark located?
The NPPES record lists a practice address at 55 Fruit Street, Boston, MA, 02114. Phone: (617) 724-4000. Providers update this record themselves, so call before visiting.
How can I verify John Ross Clark's license?
NPPES lists Massachusetts license number 49154, 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 Ross Clark prescribe under Medicare Part D?
In 2024, John Ross Clark had 54 Medicare Part D claims for 13 beneficiaries; the average among hematology & oncology physician prescribers was 877. 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.