William Hillmann, MD
NPI 1669819892 · Internal Medicine Physician · Boston, MA
Enrolled with Medicare as Practitioner - Hospitalist · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Hillmann, MD is a Internal Medicine Physician provider in Boston, MA (NPI 1669819892).
Provider details
- NPI number
- 1669819892
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- L-255382 (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
13 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
197 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) |
|---|---|---|
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 93 | $82 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 50 Minutes99233 | 68 | $123 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 20 | $181 |
| Hospital Discharge Day Management, 30 Minutes Or Less99238 | 16 | $86 |
Typical Medicare-allowed amounts for these services range $82–$181 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
Practice location
Mailing address
Registry dates
- Enumerated
- 2013-05-29
- Last updated
- 2013-05-29
Frequently asked questions
- What is William Hillmann's NPI number?
- William Hillmann's National Provider Identifier (NPI) is 1669819892, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Hillmann's specialty?
- William Hillmann is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is William Hillmann located?
- William Hillmann's practice location on file with NPPES is Massachusetts General Hospital, Boston, MA 02114.
- What is William Hillmann's phone number?
- The practice phone number listed in the NPPES registry for William Hillmann is (617) 726-2865.
- Does William Hillmann accept Medicare?
- William Hillmann is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Hillmann's NPI active?
- Yes — William Hillmann's NPI (1669819892) is active in the NPPES registry as of the last update on 2013-05-29.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.