Callie O'Brien, NP
NPI 1407400393 · Adult Health Nurse Practitioner · Boston, MA
Enrolled with Medicare as Practitioner - Nurse Practitioner · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Callie O'Brien, NP is a Adult Health Nurse Practitioner provider in Boston, MA (NPI 1407400393).
Provider details
- NPI number
- 1407400393
- Entity type
- Individual
- Primary specialty
- Adult Health Nurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- NP
- Sex
- Female
- Sole proprietor
- No
- License
- RN2294535 (MA)
Specialties & taxonomies
Physician Assistants & Advanced Practice Nursing Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
6 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
289 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 | 143 | $69 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 50 Minutes99233 | 72 | $105 |
| Initial Hospital Care With Straightforward Or Low-Level Medical Decision Making, If Using Time, at Least 55 Minutes99222 | 52 | $114 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 22 | $154 |
Typical Medicare-allowed amounts for these services range $69–$154 (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
- 2019-07-29
- Last updated
- 2026-02-22
- Certified
- 2026-02-22
Frequently asked questions
- What is Callie O'Brien's NPI number?
- Callie O'Brien's National Provider Identifier (NPI) is 1407400393, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Callie O'Brien's specialty?
- Callie O'Brien is listed in the NPPES registry with a primary specialty of Adult Health Nurse Practitioner (Physician Assistants & Advanced Practice Nursing Providers).
- Where is Callie O'Brien located?
- Callie O'Brien's practice location on file with NPPES is 450 Brookline Ave, Boston, MA 02215-5418.
- What is Callie O'Brien's phone number?
- The practice phone number listed in the NPPES registry for Callie O'Brien is (617) 632-3000.
- Does Callie O'Brien accept Medicare?
- Callie 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 Callie O'Brien's NPI active?
- Yes — Callie O'Brien's NPI (1407400393) is active in the NPPES registry as of the last update on 2026-02-22.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.