John Clark
NPI 1871550244 · Hematology & Oncology Physician · Boston, MA
Enrolled with Medicare as Practitioner - Medical Oncology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
John Clark is a Hematology & Oncology Physician provider in Boston, MA (NPI 1871550244).
Provider details
- NPI number
- 1871550244
- Entity type
- Individual
- Primary specialty
- Hematology & Oncology PhysicianAllopathic & Osteopathic Physicians
- Sex
- Male
- Sole proprietor
- No
- License
- 49154 (MA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure33% of score
20 yrs in NPPES registry
- Profile completeness33% of score
100% of core fields populated
- Practice footprint20% of score
1 documented practice location
- Open Payments transparency13% of score
Has Open Payments disclosures (2024)
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$19 across 1 record (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-04-28
- Last updated
- 2013-01-16
Frequently asked questions
- What is John Clark's NPI number?
- John Clark's National Provider Identifier (NPI) is 1871550244, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is John Clark's specialty?
- John Clark is listed in the NPPES registry with a primary specialty of Hematology & Oncology Physician (Allopathic & Osteopathic Physicians).
- Where is John Clark located?
- John Clark's practice location on file with NPPES is 55 Fruit Street, Boston, MA 02114-2696.
- What is John Clark's phone number?
- The practice phone number listed in the NPPES registry for John Clark is (617) 724-4000.
- Does John Clark accept Medicare?
- John Clark is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is John Clark's NPI active?
- Yes — John Clark's NPI (1871550244) is active in the NPPES registry as of the last update on 2013-01-16.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.