NPI registry status
Active
2026 NPPES data Gastroenterology Physician NPI 1619048030 MD
Verify on CMS → Thomas McMahon, MD
Gastroenterology Physician in Wareham, 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 17,061 in Gastroenterology 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
59
Medicare Part D claims · 36 beneficiaries · Gastroenterology Physician avg: 848
Generic prescribing
71%
generic claims · 29% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2024
What the federal data shows
Thomas McMahon, MD filed 59 Medicare Part D claims in 2024 as a Gastroenterology Physician in Wareham, Massachusetts, prescribing 71% generic.
- 59
- Part D claims, 2024
- 71%
- generic prescribing
- Likely
- board-certified (heuristic)
- ≥0th
- pct by Part D claim volume (lower-bound band)
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.
Federal trust snapshot
What official records show about Thomas McMahon, MD
Federal records show an active NPI with Medicare Part D prescribing activity — verifiable registry data, not a proprietary rating.
- Verified
NPI registry status
Active listing in the CMS National Provider Identifier Registry (NPI 1619048030), first enumerated 11/10/2006.
Source: CMS NPPES
- Reported
Medicare Part D participation
Filed 59 Medicare Part D prescription claims in the 2023 CMS public use file — indicates active Medicare prescribing participation.
Source: CMS Part D Prescriber PUF
- Reported
Board certification signal
Heuristic suggests board-certified status based on ABMS-eligible specialty taxonomy plus active CMS participation signals — not a direct ABMS verification.
- Reported
Hospital affiliations
3 CMS Care Compare hospital affiliations on record — practice footprint from the Doctors and Clinicians file.
Source: CMS Care Compare
- State context
State board disciplinary context
Massachusetts statewide board action statistics are published annually — these figures describe aggregate state activity, not Thomas McMahon, MD's individual license status. Verify directly with the state medical board.
Source: BORIM annual report 2023
- Not in federal data
Individual sanction lookup
PlainDoctor does not publish per-provider disciplinary determinations. Confirm current license and any individual actions through the state medical board or FSMB verification service.
Source: State medical board / FSMB
This trust snapshot summarizes only what appears in federal CMS/NPPES public records. It is not a composite score, star rating, patient review, or clinical recommendation. PlainDoctor never fabricates reviews or AggregateRating schema.
CMS NPPES provider registry desk
NPI 1619048030 · Gastroenterology Physician
NPI-10 · ENUM-LEGACY · TAX-MID · RX-TRACE · BOOK-LIGHT · PHOTO-ENUM
- NPI-10 1619048030
- ENUM-LEGACY 2006
- TAX-MID 17K Gastroenterology Physician
- RX-TRACE 59
- BOOK-LIGHT 538 in Massachusetts
- PHOTO-ENUM Chuang Hung · 2006
Thomas McMahon, MD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2024, across all CMS prescribers nationally
59 ≥ 0th percentile 0% of 1,416,883 prescribers are in lower value bands
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.
The percentile is a conservative 100-claim band: it counts only prescribers in lower claim-volume bands. Medicare Part D claim volume is activity context, not a quality measure or recommendation. See methodology § corpus placement.
Source CMS Medicare Part D Prescriber Public Use File · 2024
✓
Board certification likely (heuristic, not verified)
Thomas McMahon, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 3 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 Thomas McMahon, MD?
Quality data not reportedPrimary specialty
Gastroenterology Physician
Medicare Part D claims
59 93% vs specialty avg
Specialty distribution in Massachusetts
How Gastroenterology 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 Gastroenterology 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).
Practice Address
Provider Details
| NPI | 1619048030 |
|---|---|
| Specialty | Gastroenterology Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 11/10/2006 |
Hospital and facility affiliations
Facilities where Thomas McMahon, MD 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.
According to CMS billing records, Thomas McMahon, MD is affiliated with 3 Medicare-billing facilities across 3 states.
Geisinger Clinic
Pittston, PA
Lakewood Health System
Staples, MN
Critical Access Hospitals
CMS CCN: 241329
Southcoast Physicians Group Inc
Wareham, 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).
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 Thomas McMahon, MD. To verify Thomas McMahon, MD'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 · Above average
Thomas McMahon, MD - brand share 29.0%
Gastroenterology Physician average
29% brand-name claims vs 71% generic, on 59 2024 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 2024.
59
Total Claims
$25K
Total Drug Cost
36
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 90.333
- Total Day Supply
- 2,482
- Brand vs Generic
- 29% brand / 71% generic
- Brand Drug Cost
- $21K
- Generic Drug Cost
- $4K
Patient Demographics
- Average Patient Age
- 73.4 years
- Avg HCC Risk Score
- 1.39
Gastroenterology Physician Overview
How Thomas McMahon, MD fits within the Gastroenterology Physician landscape nationally.
17,061
Gastroenterology Physician Providers in US
54
States with Gastroenterology Physician
848
Avg Claims per Provider
Thomas McMahon, MD's 59 claims are below the specialty average of 848.
Nationwide Gastroenterology Physician peers with similar MIPS or enrollment year
Two federal-record peer sets for McMahon, both outside Massachusetts so the neighborhoods are not geographic containment.
Same NPPES enumeration year (2006)
Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.
Nearby Gastroenterology Physician Providers in Massachusetts
Other clinicians with the same primary specialty enrolled in Massachusetts, drawn from the same CMS NPPES roster as McMahon.
One of 538 Gastroenterology Physician providers enrolled in Massachusetts, 5 are shown here.
Dr. Robert Aaron
MD
Stoneham, MA
Dr. Michael Aaronson
MD
Beverly, MA
Dr. Diane Abraczinskas
MD
Boston, MA
Dr. Lynne Ahn
MD
Framingham, MA
Dr. Hiroyuki Aihara
M.D.
Boston, MA
Compare Gastroenterology Physician nationally: see state-by-state distribution →
Frequently Asked Questions
What is Thomas McMahon, MD's specialty? ▼
Thomas McMahon, MD specializes in Gastroenterology Physician and practices in Wareham, Massachusetts. Credentials: MD.
How much does Thomas McMahon, MD prescribe under Medicare Part D? ▼
In 2024, Thomas McMahon, MD wrote 59 Medicare Part D claims totaling $25K in drug costs for 36 beneficiaries.
Where is Thomas McMahon, MD located? ▼
Thomas McMahon, MD is located at 100 ROSEBROOK WAY, Wareham, MA, 02571. Phone: (508) 973-4974.
What is Thomas McMahon, MD's NPI number? ▼
Thomas McMahon, MD's National Provider Identifier (NPI) is 1619048030, issued on 11/10/2006.
Does Thomas McMahon, MD prescribe more brand-name or generic drugs? ▼
Thomas McMahon, MD's prescribing is 29% brand-name and 71% generic drugs by claim count, with $21K in brand drug costs.
How many Gastroenterology Physician providers are there in the US? ▼
There are 17,061 Gastroenterology Physician providers across 54 states in the US. The average Gastroenterology Physician provider writes 848 Medicare Part D claims per year.
Does Thomas McMahon, MD accept Medicare? ▼
Thomas McMahon, MD appears in CMS Medicare data with 59 Part D claims and 36 Medicare beneficiaries in 2024. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Thomas McMahon, MD's credentials? ▼
Thomas McMahon, MD's NPI is 1619048030 with credentials MD. 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 (2024). 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 August 2026 (NPPES) / 2024 (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
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 August 2026.