Steven Master, M.D.
NPI 1255564837 · Internal Medicine Physician · Cambridge, MA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Steven Master, M.D. is a Internal Medicine Physician provider in Cambridge, MA (NPI 1255564837).
Provider details
- NPI number
- 1255564837
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- 248246 (MA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Student, Health Care
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
16 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
975 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 50 Minutes99233 | 324 | $124 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 313 | $82 |
| Hospital Discharge Day Management, More Than 30 Minutes99239 | 138 | $121 |
| Subsequent Hospital Care With Straightforward Or Low Level of Medical Decision Making, Per Day, If Using Time, at Least 25 Minutes99231 | 72 | $52 |
| Hospital Discharge Day Management, 30 Minutes Or Less99238 | 48 | $85 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2009-08-28
- Last updated
- 2014-09-03
Frequently asked questions
- What is Steven Master's NPI number?
- Steven Master's National Provider Identifier (NPI) is 1255564837, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Steven Master's specialty?
- Steven Master is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Steven Master located?
- Steven Master's practice location on file with NPPES is 330 Mount Auburn St, Cambridge, MA 02138-5502.
- What is Steven Master's phone number?
- The practice phone number listed in the NPPES registry for Steven Master is (617) 499-5112.
- Does Steven Master accept Medicare?
- Steven Master is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Steven Master's NPI active?
- Yes — Steven Master's NPI (1255564837) is active in the NPPES registry as of the last update on 2014-09-03.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.