William Tollefsen, MD
NPI 1841462876 · Emergency Medicine Physician · Worcester, MA
Enrolled with Medicare as Practitioner - Emergency Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Tollefsen, MD is a Emergency Medicine Physician provider in Worcester, MA (NPI 1841462876).
Provider details
- NPI number
- 1841462876
- Entity type
- Individual
- Primary specialty
- Emergency Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 243758 (MA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
18 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
353 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Emergency Department Visit With High Level of Medical Decision Making99285 | 136 | $179 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 64 | $120 |
| Emergency Department Visit With Moderate Level of Medical Decision Making99284 | 43 | $124 |
| Critical Care, First 30-74 Minutes99291 | 24 | $220 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 23 | $170 |
| New Patient Office Or Other Outpatient Visit With Low Level of Medical Decision Making, If Using Time, 30 Minutes Or More99203 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2008-03-31
- Last updated
- 2012-11-13
Frequently asked questions
- What is William Tollefsen's NPI number?
- William Tollefsen's National Provider Identifier (NPI) is 1841462876, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Tollefsen's specialty?
- William Tollefsen is listed in the NPPES registry with a primary specialty of Emergency Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is William Tollefsen located?
- William Tollefsen's practice location on file with NPPES is 119 Belmont St, Worcester, MA 01605-2903.
- What is William Tollefsen's phone number?
- The practice phone number listed in the NPPES registry for William Tollefsen is (508) 421-1400.
- Does William Tollefsen accept Medicare?
- William Tollefsen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Tollefsen's NPI active?
- Yes — William Tollefsen's NPI (1841462876) is active in the NPPES registry as of the last update on 2012-11-13.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.