NPI registry status
Active
2026 NPPES data Hematology & Oncology Physician NPI 1265669659 M.D.
Verify on CMS → Rebecca Karp, M.D.
Hematology & Oncology Physician in Boston, Massachusetts.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 11,232 in Hematology & Oncology Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
234
Medicare Part D claims · 61 beneficiaries · Hematology & Oncology Physician avg: 847
Generic prescribing
0%
generic claims · 56% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$6.9K
2 payments · CMS Open Payments (Sunshine Act)
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Rebecca Karp, M.D. filed 234 Medicare Part D claims in 2023 as a Hematology & Oncology Physician in Boston, Massachusetts, prescribing 0% generic.
- 234
- Part D claims, 2023
- 0%
- generic prescribing
- Likely
- board-certified (heuristic)
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Rebecca Karp, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
234 49th percentile higher than 49% of 1,370,886 prescribers
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source CMS Medicare Part D Prescriber Public Use File · 2023
✓
Board certification likely (heuristic, not verified)
Rebecca Karp, M.D. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 2 hospital affiliations - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Rebecca Karp, M.D.?
Quality data not reportedPrimary specialty
Hematology & Oncology Physician
Medicare Part D claims
234 72% vs specialty avg
Specialty distribution in Massachusetts
How Hematology & Oncology Physician compares to other specialties among Massachusetts providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Hematology & Oncology Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Rebecca Karp, M.D. appears in the CMS NPPES registry as a Hematology & Oncology Physician provider holding M.D. credentials at 330 BROOKLINE AVE, Boston, MA, 02215, with a listed phone of (617) 667-2100. NPI 1265669659 was issued on 06/12/2009.
Medicare Part D records for calendar year 2023 show 234 prescription claims written by this provider, covering 61 Medicare beneficiaries and totaling roughly $822K in drug spend, split 56% brand-name and 0% generic by claim count.
Hematology & Oncology Physician is a mid-sized specialty nationwide, with 11,232 enrolled providers across 54 states and an average of 847 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline.
Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist, always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.
Practice Address
Provider Details
| NPI | 1265669659 |
|---|---|
| Specialty | Hematology & Oncology Physician |
| Credentials | M.D. |
| Gender | Female |
| NPI Issued | 06/12/2009 |
Hospital and facility affiliations
Facilities where Rebecca Karp, M.D. bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.
Massachusetts General Physicians Organization Inc
Boston, MA
The General Hospital Corporation
Waltham, MA
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
Industry payments received (2024) - CMS Open Payments transparency data
The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for Rebecca Karp, M.D.. Source: openpaymentsdata.cms.gov.
Total received
$6.9K
Largest payer
RECORDATI_RARE_DISEASES_INC.
Most common payment type
Compensation for services other than consulting, including serving as faculty or as a speaker at a venue other than a continuing education program
Industry payments are not necessarily indicators of bias, they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.
License & disciplinary context - Massachusetts BORIM 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~38K Massachusetts medical licensees in 2023 - they are NOT specific to Rebecca Karp, M.D.. To verify Rebecca Karp, M.D.'s current license status, search the BORIM public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
80
Total board actions, Massachusetts 2023
Across 78 cases
2.11
Actions per 1,000 licensees
Massachusetts statewide rate
probation
Most common action type
29 cases
BORIM publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the Massachusetts disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Brand vs generic prescribing mix · Brand-heavy
Rebecca Karp, M.D. - brand share 56.0%
Hematology & Oncology Physician average
56% brand-name claims vs 0% generic, on 234 2023 Medicare Part D claims.
The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
234
Total Claims
$822K
Total Drug Cost
61
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 401
- Total Day Supply
- 11,388
- Brand vs Generic
- 56% brand / 0% generic
- Brand Drug Cost
- $813K
Patient Demographics
- Average Patient Age
- 68.9 years
- Avg HCC Risk Score
- 2.21
- Gender Split
- 62% female / 38% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Rebecca Karp, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Eliquis
Eliquis
44 claims
- Hydroxyurea
Hydroxyurea
40 claims
- Jakafi 17
Jakafi
17 claims
- Enoxaparin Sodium 15
Enoxaparin Sodium
15 claims
- Warfarin Sodium 13
Warfarin Sodium
13 claims
- Bosulif 11
Bosulif
11 claims
- Doptelet 11
Doptelet
11 claims
| Drug | Claims |
|---|---|
| Eliquis Apixaban | 44 |
| Hydroxyurea | 40 |
| Jakafi Ruxolitinib Phosphate | 17 |
| Enoxaparin Sodium | 15 |
| Warfarin Sodium | 13 |
| Bosulif Bosutinib | 11 |
| Doptelet Avatrombopag Maleate | 11 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Hematology & Oncology Physician Overview
How Rebecca Karp, M.D. fits within the Hematology & Oncology Physician landscape nationally.
11,232
Hematology & Oncology Physician Providers in US
54
States with Hematology & Oncology Physician
847
Avg Claims per Provider
Rebecca Karp, M.D.'s 234 claims are below the specialty average of 847.
Nearby Hematology & Oncology Physician Providers in Massachusetts
Other clinicians with the same primary specialty enrolled in Massachusetts, drawn from the same CMS NPPES roster as Karp.
Dr. Gregory Abel
MD
Boston, MA
Dr. Rachel Abelman
MD
Boston, MA
Dr. Karim Abou-Nassar
MD
Boston, MA
Dr. Inas Abuali
M.D.
Boston, MA
Dr. Maureen Achebe
MD, MPH
Boston, MA
Compare Hematology & Oncology Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the Massachusetts medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Hematology & Oncology Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
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Frequently Asked Questions
What is Rebecca Karp, M.D.'s specialty? ▼
Rebecca Karp, M.D. specializes in Hematology & Oncology Physician and practices in Boston, Massachusetts. Credentials: M.D..
How much does Rebecca Karp, M.D. prescribe under Medicare Part D? ▼
In 2023, Rebecca Karp, M.D. wrote 234 Medicare Part D claims totaling $822K in drug costs for 61 beneficiaries.
Where is Rebecca Karp, M.D. located? ▼
Rebecca Karp, M.D. is located at 330 BROOKLINE AVE, Boston, MA, 02215. Phone: (617) 667-2100.
What is Rebecca Karp, M.D.'s NPI number? ▼
Rebecca Karp, M.D.'s National Provider Identifier (NPI) is 1265669659, issued on 06/12/2009.
Does Rebecca Karp, M.D. prescribe more brand-name or generic drugs? ▼
Rebecca Karp, M.D.'s prescribing is 56% brand-name and 0% generic drugs by claim count, with $813K in brand drug costs.
How many Hematology & Oncology Physician providers are there in the US? ▼
There are 11,232 Hematology & Oncology Physician providers across 54 states in the US. The average Hematology & Oncology Physician provider writes 847 Medicare Part D claims per year.
What drugs does Rebecca Karp, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, Rebecca Karp, M.D.'s most frequently prescribed drugs include Eliquis, Hydroxyurea, Jakafi. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Rebecca Karp, M.D. accept Medicare? ▼
Rebecca Karp, M.D. appears in CMS Medicare data with 234 Part D claims and 61 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Rebecca Karp, M.D.'s credentials? ▼
Rebecca Karp, M.D.'s NPI is 1265669659 with credentials M.D.. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Compiled from official public sources by the PlainDoctor editorial team.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.