Dr. William W. Tollefsen, MD
- Medicare services, 2024
- 353
- Medicare patients, 2024
- 315
- Part D claims, 2024
- 52
- MIPS score, 2024
- 87
- Hospital affiliations
- 1
- Practice address
- 55 Fogg Road, South Weymouth, MA 02190
- Practice phone
- Call (781) 340-8000
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. Tollefsen's professional email, personal email and mobile number
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Dr. William W. Tollefsen is an emergency medicine physician in South Weymouth, Massachusetts
Dr. Tollefsen practices at South Shore Hospital in South Weymouth, Massachusetts, part of South Shore Health System.
Dr. Tollefsen's NPI, 1841462876, was assigned on March 31, 2008. Dr. Tollefsen graduated from New York Medical College in 2008. Dr. Tollefsen holds Massachusetts license 243758.
- NPI
- 1841462876NPI Registry (opens in a new tab)
- Medicare PAC ID
- 3870741127
- NPI enumeration date
- March 31, 2008
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (781) 340-8000
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 44
- Medical school graduation
- 2008
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. William W. Tollefsen practices at South Shore Hospital in South Weymouth, Massachusetts
Dr. Tollefsen's primary practice is South Shore Hospital, at 55 Fogg Road, South Weymouth, MA 02190 in Norfolk County. The practice phone is (781) 340-8000.
- South Shore Hospital55 Fogg Road, South Weymouth, MA 02190 · Norfolk CountyPhone(781) 340-8000
Source: Dmand AI Affiliation Data
Dr. William W. Tollefsen is affiliated with 1 site of care and 2 medical groups
Dr. Tollefsen's primary practice is South Shore Hospital in South Weymouth, Massachusetts, part of South Shore Health System. The medical group on file is Coastal Medical Associates. Dmand AI also links Dr. Tollefsen to 1 more medical group, named with a free account.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. William W. Tollefsen's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Tollefsen practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| South Shore Hospital | Available with a free account |
| +1 medical group | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. William W. Tollefsen is one of 1,483 emergency medicine physicians in Massachusetts
Emergency medicine is Dr. Tollefsen's primary specialty in the NPI Registry, under taxonomy code 207P00000X. Dr. Tollefsen is licensed in Massachusetts.
Specialties and state licenses
- Emergency medicine, MassachusettsPrimary
Emergency medicine physicians near Dr. Tollefsen
Counts of emergency medicine physicians with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. William W. Tollefsen billed Medicare for 353 services in 2024
CMS data shows 353 Medicare services from Dr. Tollefsen across 9 procedure codes in 2024, for 315 Medicare patients. Medicare paid $38,678 for them.
Dr. Tollefsen's Medicare services by type, 2023 to 2024
- 2023
- 2024
- Office and hospital visits
- 2023: 3502024: 31011%
- Lab and pathology
- 2023: 292024: 29No change
- Imaging
- 2023: 122024: 1417%
- Other services
- 2023: 162024: 0100%
Where Dr. Tollefsen's Medicare services took place, 2024
- In an office15042%
- In a facility20358%
Dr. Tollefsen compared with the Massachusetts median for emergency medicine physicians, 2024
- Dr. Tollefsen
- Massachusetts median
- Medicare services
- 353vs 341Close to median
- Medicare patients
- 315vs 3377% below
- Part D claims
- 22vs 3639% below
Medians across 1,477 emergency medicine physicians in Massachusetts with Dmand AI profiles that report each measure.
Dr. Tollefsen's most billed Medicare procedure codes, 2024
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
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Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Tollefsen and other emergency medicine physicians in Massachusetts.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. William W. Tollefsen treated 315 Medicare patients in 2024, average age 75
CMS counts 315 Medicare patients who saw Dr. Tollefsen in 2024. The largest group is 75 to 84, with 114 patients. 75% of them have high blood pressure, and 75% have high cholesterol. 22% are also on Medicaid. Their average risk score is 1.78, where 1.00 is the Medicare average, so they are sicker than most Medicare patients.
Across all payers, Dmand AI patient panel data puts Dr. Tollefsen's median patient age at 62, with 54% women.
Dr. Tollefsen's Medicare patients by age, 2024
Dr. Tollefsen's Medicare patients by sex, 2024
- Women18057%
- Men13543%
Chronic conditions among Dr. Tollefsen's Medicare patients, 2024
- High blood pressure75%
- High cholesterol75%
- Arthritis49%
- Anxiety43%
- Mood disorders40%
- Chronic kidney disease38%
- Ischemic heart disease37%
- Depression33%
Share of Medicare patients with each condition. A patient can have several.
Dr. Tollefsen's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 62
Patient panel by sex, all payers
- Women54%
- Men45%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. William W. Tollefsen wrote 52 Medicare Part D claims in 2024
In 2024, Dr. Tollefsen wrote 52 Medicare Part D claims for 42 patients. 83% of them were for generic drugs. CMS names the drug for 22 of them, across 2 drugs with 11 or more claims each, at $841 in total drug cost. In 2021, CMS named 12 claims across 1 drug.
Dr. Tollefsen's Part D claims by kind of drug, 2024
- Generic43 claims83%
- Brand-name and other9 claims17%
Dr. Tollefsen's most prescribed drugs by claims, 2023
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. Tollefsen's Part D claims, 2024
- Antibiotics27%14 of 52 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Part D claims for drugs CMS names, 2021 to 2023
- 2021
- 2023
- Claims for drugs CMS names
- 2021: 122023: 2283%
Drugs named by CMS: 2 in 2023, 1 in 2021.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
Dr. William W. Tollefsen scored 87 out of 100 in Medicare's MIPS program for 2024
CMS publishes a Merit-based Incentive Payment System (MIPS) score of 87 out of 100 for Dr. Tollefsen for performance year 2024, reported as part of a group. Dr. Tollefsen accepts Medicare assignment, so Medicare's approved amount is taken as full payment.
- Accepts Medicare assignment
- Yes
Dr. Tollefsen's MIPS scores, performance year 2024
- 87of 100Final score
- 88.1of 100Quality
- 71of 100Promoting Interoperability
- 40of 100Improvement Activities
- 78of 100Cost
Each score is out of 100. The final score weighs the categories CMS scored for this clinician.
Sources: Doctors and Clinicians National Downloadable File (CMS); and Clinician Public Reporting: Overall MIPS Performance (CMS), 2024 data, released September 10, 2026
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Dr. William W. Tollefsen received $9,581 in industry payments from 2022 to 2023
CMS Open Payments shows 2 general payments to Dr. Tollefsen from 2 drug and device companies from 2022 to 2023. Consulting fees make up the largest share, 98% of the total. Nihon Kohden America, Inc. paid the most, $9,400.
General payments to Dr. Tollefsen by program year, 2022 to 2023
General payments to Dr. Tollefsen by kind, 2022 to 2023
- Consulting fees$9,40098%
- Food and beverage$1812%
Companies that paid Dr. Tollefsen the most, 2022 to 2023
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. William W. Tollefsen graduated from New York Medical College
Dr. Tollefsen graduated from New York Medical College in 2008.
- Medical school
Source: Dmand AI Professional Profile Data
Sources for Dr. William W. Tollefsen's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab)Clinician Public Reporting: Overall MIPS Performance (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. William W. Tollefsen
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. William W. Tollefsen's NPI number?
Dr. William W. Tollefsen's NPI number is 1841462876. It was assigned on March 31, 2008, and it is active in the NPI Registry.
What kind of doctor is Dr. William W. Tollefsen?
Dr. William W. Tollefsen is an emergency medicine physician in South Weymouth, Massachusetts. The primary specialty in the NPI Registry is Emergency Medicine Physician (taxonomy code 207P00000X).
Where does Dr. William W. Tollefsen practice?
Dr. Tollefsen practices at 55 Fogg Road, South Weymouth, MA 02190. Dr. Tollefsen's primary practice is South Shore Hospital in South Weymouth, Massachusetts, part of South Shore Health System. Dmand AI also links Dr. Tollefsen to 1 medical group.
What is Dr. William W. Tollefsen's office phone number?
The practice phone on file for Dr. Tollefsen is (781) 340-8000.
What is Dr. William W. Tollefsen's medical license number?
Dr. Tollefsen holds Massachusetts license 243758.
Which hospitals is Dr. William W. Tollefsen affiliated with?
Dr. Tollefsen practices at South Shore Hospital in South Weymouth, Massachusetts.
What medical group is Dr. William W. Tollefsen part of?
Dr. Tollefsen is linked to Coastal Medical Associates. Dmand AI links Dr. Tollefsen to 1 more medical group.
Does Dr. William W. Tollefsen accept Medicare?
Yes. CMS data shows Dr. Tollefsen billed Medicare for 353 services in 2024, and Dr. Tollefsen accepts Medicare assignment.
What is Dr. William W. Tollefsen's MIPS score?
Dr. Tollefsen's MIPS final score for performance year 2024 is 87 out of 100, reported as part of a group.
How many Medicare patients does Dr. William W. Tollefsen see?
CMS counts 315 Medicare patients who saw Dr. Tollefsen in 2024, with an average age of 75.
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What services does Dr. William W. Tollefsen bill to Medicare?
In 2024, Dr. Tollefsen's most billed Medicare services were emergency department visit (99285), office visit, established patient (99214) and emergency department visit (99284).
Where did Dr. William W. Tollefsen go to medical school?
Dr. Tollefsen graduated from New York Medical College in 2008.
What drugs does Dr. William W. Tollefsen prescribe most?
In 2023 Medicare Part D data, Dr. Tollefsen's most prescribed drugs by claims were Cefpodoxime Proxetil and Doxycycline Hyclate.
Has Dr. William W. Tollefsen received payments from drug or device companies?
CMS Open Payments shows $9,581 in general payments to Dr. Tollefsen from 2 companies from 2022 to 2023. The largest total came from Nihon Kohden America, Inc.
How long has Dr. William W. Tollefsen been practicing?
Dr. Tollefsen graduated from medical school in 2008, 18 years ago.
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