Mary Ellen O'Brien, M.D.
NPI 1144425000 · Internal Medicine Physician · Providence, RI
Enrolled with Medicare as Practitioner - Hospitalist · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mary Ellen O'Brien, M.D. is a Internal Medicine Physician provider in Providence, RI (NPI 1144425000).
Provider details
- NPI number
- 1144425000
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Female
- Sole proprietor
- No
- License
- LP01243 (RI)
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
19 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
508 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) |
|---|---|---|
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 395 | $181 |
| Initial Hospital Care With Straightforward Or Low-Level Medical Decision Making, If Using Time, at Least 55 Minutes99222 | 68 | $136 |
| Initial Hospital Care With Straightforward Or Low Level of Medical Decision Making, Per Day, If Using Time, at Least 40 Minutes99221 | 22 | $86 |
| Critical Care, First 30-74 Minutes99291 | 12 | $220 |
| Initial Hospital Care With Same-Day Admission and Discharge With Moderate Level of Medical Decision Making, Per Day, If Using Time, at Least 70 Minutes99235 | 11 | $166 |
Typical Medicare-allowed amounts for these services range $86–$220 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, 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
- 2007-06-19
- Last updated
- 2010-01-22
Frequently asked questions
- What is Mary Ellen O'Brien's NPI number?
- Mary Ellen O'Brien's National Provider Identifier (NPI) is 1144425000, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mary Ellen O'Brien's specialty?
- Mary Ellen O'Brien is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Mary Ellen O'Brien located?
- Mary Ellen O'Brien's practice location on file with NPPES is 593 Eddy St, Providence, RI 02903-4923.
- What is Mary Ellen O'Brien's phone number?
- The practice phone number listed in the NPPES registry for Mary Ellen O'Brien is (401) 444-4083.
- Does Mary Ellen O'Brien accept Medicare?
- Mary Ellen O'Brien is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mary Ellen O'Brien's NPI active?
- Yes — Mary Ellen O'Brien's NPI (1144425000) is active in the NPPES registry as of the last update on 2010-01-22.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.