2026 NPPES data Infectious Disease Physician NPI 1265505499 M.D.
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William Charini, M.D.

Infectious Disease Physician in Lawrence, 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 8,292 in Infectious Disease 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
93
Medicare Part D claims · 29 beneficiaries · Infectious Disease Physician avg: 816
Generic prescribing
80%
generic claims · 20% brand-name · higher generic rates reduce patient out-of-pocket costs
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

William Charini, M.D. filed 93 Medicare Part D claims in 2023 as a Infectious Disease Physician in Lawrence, Massachusetts, prescribing 80% generic.

93
Part D claims, 2023
80%
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.

William Charini, M.D.'s Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023, across all CMS prescribers nationally

93 0th percentile higher than 0% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). This entry sits in this band. 200–400: 182,923 prescribers (13%). Above this entry. 400–600: 90,619 prescribers (7%). Above this entry. 600–800: 56,224 prescribers (4%). Above this entry. 800–1,000: 40,919 prescribers (3%). Above this entry. 1,000–1,200: 31,827 prescribers (2%). Above this entry. 1,200–1,400: 26,224 prescribers (2%). Above this entry. 1,400–1,600: 21,710 prescribers (2%). Above this entry. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2K+: 213,991 prescribers (16%). Above this entry. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

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)

William Charini, M.D. 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).

What does the federal data show about William Charini, M.D.?

Quality data not reported

NPI registry status

Active

Issued 11/16/2006

NPI 1265505499

Primary specialty

Infectious Disease Physician

Mid-sized

8,292 US NPIs in this specialty

Medicare Part D claims

93 89% vs specialty avg

2023 prescription claims

Specialty avg: 816

Specialty distribution in Massachusetts

How Infectious Disease Physician compares to other specialties among Massachusetts providers

Massachusetts providers

Largest specialties in Massachusetts (% of in-state providers)

Mental Health Counselor - 8.3%Mental Health Counselor8.3%Clinical Social Worker - 7.8%Clinical Social Worker7.8%Student in an Organized Health Care Education/Training Program - 6.2%Student in an Organized Health Care Education/Training Program6.2%Behavior Technician - 4.9%Behavior Technician4.9%Counselor - 4.3%Counselor4.3%Internal Medicine Physician - 3.7%Internal Medicine Physician3.7%Infectious Disease Physician - 0.2%Infectious Disease Physician0.2%
Largest specialties in Massachusetts (% of in-state 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 Infectious Disease Physician. Verify directly:

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).

William Charini, M.D. appears in the CMS NPPES registry as a Infectious Disease Physician provider holding M.D. credentials at 1 GENERAL ST, Lawrence, MA, 01841, with a listed phone of (978) 683-4000. NPI 1265505499 was issued on 11/16/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Charini 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 records for calendar year 2023 show 93 prescription claims written by this provider, covering 29 Medicare beneficiaries and totaling roughly $87K in drug spend, split 20% brand-name and 80% generic by claim count. These figures capture only Medicare Part D, commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Infectious Disease Physician is a mid-sized specialty nationwide, with 8,292 enrolled providers across 54 states and an average of 816 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

1 GENERAL ST
Lawrence, MA 01841

Provider Details

NPI 1265505499
Specialty Infectious Disease Physician
Credentials M.D.
Gender Male
NPI Issued 11/16/2006

Hospital and facility affiliations

Facilities where William Charini, 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.

Mass General Brigham Medical Group Northern Massachusetts Inc
Salem, 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 William Charini, M.D.. To verify William Charini, 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 · Typical

William Charini, M.D. - brand share 20.0%
Infectious Disease Physician average

20% brand-name claims vs 80% generic, on 93 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.

93
Total Claims
$87K
Total Drug Cost
29
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
111
Total Day Supply
2,579
Brand vs Generic
20% brand / 80% generic
Brand Drug Cost
$77K
Generic Drug Cost
$10K
Antibiotic Claims
41

Patient Demographics

Average Patient Age
68.3 years
Avg HCC Risk Score
1.68

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

What William Charini, M.D. prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Vancomycin Hcl
15
Stribild
Elviteg/Cob/Emtri/Tenofo Disop
12
Efavirenz-Emtric-Tenofov Disop
Efavirenz/Emtricit/Tenofovr Df
11

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Infectious Disease Physician Overview

How William Charini, M.D. fits within the Infectious Disease Physician landscape nationally.

8,292
Infectious Disease Physician Providers in US
54
States with Infectious Disease Physician
816
Avg Claims per Provider

William Charini, M.D.'s 93 claims are below the specialty average of 816.

Nearby Infectious Disease Physician Providers in Massachusetts

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

Compare Infectious Disease 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 Infectious Disease 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.

Frequently Asked Questions

What is William Charini, M.D.'s specialty?
William Charini, M.D. specializes in Infectious Disease Physician and practices in Lawrence, Massachusetts. Credentials: M.D..
How much does William Charini, M.D. prescribe under Medicare Part D?
In 2023, William Charini, M.D. wrote 93 Medicare Part D claims totaling $87K in drug costs for 29 beneficiaries.
Where is William Charini, M.D. located?
William Charini, M.D. is located at 1 GENERAL ST, Lawrence, MA, 01841. Phone: (978) 683-4000.
What is William Charini, M.D.'s NPI number?
William Charini, M.D.'s National Provider Identifier (NPI) is 1265505499, issued on 11/16/2006.
Does William Charini, M.D. prescribe more brand-name or generic drugs?
William Charini, M.D.'s prescribing is 20% brand-name and 80% generic drugs by claim count, with $77K in brand drug costs.
How many Infectious Disease Physician providers are there in the US?
There are 8,292 Infectious Disease Physician providers across 54 states in the US. The average Infectious Disease Physician provider writes 816 Medicare Part D claims per year.
What drugs does William Charini, M.D. prescribe most often?
Based on 2023 Medicare Part D data, William Charini, M.D.'s most frequently prescribed drugs include Vancomycin Hcl, Stribild, Efavirenz-Emtric-Tenofov Disop. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does William Charini, M.D. accept Medicare?
William Charini, M.D. appears in CMS Medicare data with 93 Part D claims and 29 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify William Charini, M.D.'s credentials?
William Charini, M.D.'s NPI is 1265505499 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

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.