2026 NPPES data Pediatric Hematology & Oncology Physician NPI 1851534481 M.D., M.P.H.
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STEPHANIE MASSARO, M.D., M.P.H.

Pediatric Hematology & Oncology Physician in NEW HAVEN, Connecticut. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
What the federal data reveals: STEPHANIE MASSARO, M.D., M.P.H. is a Pediatric Hematology & Oncology Physician ([object Object]) practicing in NEW HAVEN, Connecticut .

What stands out: STEPHANIE MASSARO, M.D., M.P.H. specializes in Pediatric Hematology & Oncology Physician and practices in NEW HAVEN, Connecticut, listed in the federal CMS National Provider Identifier registry. Every detail on this page comes straight from federal CMS records, with no proprietary rating applied.

Board certification likely (heuristic — not verified)

STEPHANIE MASSARO, M.D., M.P.H. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation — signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).

STEPHANIE MASSARO, M.D., M.P.H. at a glance

Quality data not reported

NPI registry status

Active

Issued 04/13/2009

NPI 1851534481

Primary specialty

Pediatric Hematology & Oncology Physician

Niche

2,568 US NPIs in this specialty

Specialty distribution in Connecticut

How Pediatric Hematology & Oncology Physician compares to other specialties among Connecticut providers

Connecticut providers

Pediatric Hematology & Oncology Physician share within Connecticut

1. Pediatric Hematology & Oncology Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Pediatric Hematology & Oncology Physician share within Connecticut

Specialty board-certification context

Estimated specialty board-certified rate — Pediatric Hematology & Oncology Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Pediatric Hematology & Oncology Physician ABMS/AOA estimate

Est. board-certified rate (Pediatric Hematology & Oncology Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Pediatric Hematology & Oncology Physician) — ABMS / AOA estimate

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).

STEPHANIE MASSARO, M.D., M.P.H. is a Pediatric Hematology & Oncology Physician provider practicing in NEW HAVEN, Connecticut, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: M.D., M.P.H.. NPI: 1851534481. This profile includes practice location, specialty classification, and organizational affiliations from the CMS provider registry. Provider information is self-reported to CMS and updated monthly.

STEPHANIE MASSARO, M.D., M.P.H. appears in the CMS NPPES registry as a Pediatric Hematology & Oncology Physician provider holding M.D., M.P.H. credentials at 333 CEDAR ST, NEW HAVEN, CT, 06520, with a listed phone of (203) 785-4640. NPI 1851534481 was issued on 04/13/2009. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what MASSARO most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D prescribing data is not currently published for this NPI, which typically means the provider either wrote fewer than 11 Part D claims in the most recent reporting year, does not participate in Medicare, or practices in a specialty that rarely prescribes outpatient drugs. Absence of prescribing data is not a quality signal — many Pediatric Hematology & Oncology Physician providers operate outside Part D entirely.

Pediatric Hematology & Oncology Physician is a narrow specialty nationwide, with 2,568 enrolled providers across 52 states and an average of 92 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

333 CEDAR ST
NEW HAVEN, CT 06520

Provider Details

NPI 1851534481
Specialty Pediatric Hematology & Oncology Physician
Credentials M.D., M.P.H.
Gender Female
NPI Issued 04/13/2009

Hospital and facility affiliations

Facilities where STEPHANIE MASSARO, M.D., M.P.H. 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.

YALE UNIVERSITY
TRUMBULL, CT

Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).

Pediatric Hematology & Oncology Physician Overview

How STEPHANIE MASSARO, M.D., M.P.H. fits within the Pediatric Hematology & Oncology Physician landscape nationally.

2,568
Pediatric Hematology & Oncology Physician Providers in US
52
States with Pediatric Hematology & Oncology Physician
92
Avg Claims per Provider

Nearby Pediatric Hematology & Oncology Physician Providers in Connecticut

Other clinicians with the same primary specialty enrolled in Connecticut, drawn from the same CMS NPPES roster as MASSARO.

Compare Pediatric Hematology & Oncology Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is STEPHANIE MASSARO, M.D., M.P.H.'s specialty?
STEPHANIE MASSARO, M.D., M.P.H. specializes in Pediatric Hematology & Oncology Physician and practices in NEW HAVEN, Connecticut. Credentials: M.D., M.P.H..
Where is STEPHANIE MASSARO, M.D., M.P.H. located?
STEPHANIE MASSARO, M.D., M.P.H. is located at 333 CEDAR ST, NEW HAVEN, CT, 06520. Phone: (203) 785-4640.
What is STEPHANIE MASSARO, M.D., M.P.H.'s NPI number?
STEPHANIE MASSARO, M.D., M.P.H.'s National Provider Identifier (NPI) is 1851534481, issued on 04/13/2009.
How many Pediatric Hematology & Oncology Physician providers are there in the US?
There are 2,568 Pediatric Hematology & Oncology Physician providers across 52 states in the US. The average Pediatric Hematology & Oncology Physician provider writes 92 Medicare Part D claims per year.
Does STEPHANIE MASSARO, M.D., M.P.H. accept Medicare?
STEPHANIE MASSARO, M.D., M.P.H. appears in CMS Medicare data. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify STEPHANIE MASSARO, M.D., M.P.H.'s credentials?
STEPHANIE MASSARO, M.D., M.P.H.'s NPI is 1851534481 with credentials M.D., M.P.H.. 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

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.
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