John O'Brien, A.P.R.N.
NPI 1043336258 · Certified Registered Nurse Anesthetist · Danbury, CT
Enrolled with Medicare as Practitioner - Certified Registered Nurse Anesthetist (crna) · source: CMS PECOS Public Provider Enrollment (2026.04.01)
John O'Brien, A.P.R.N. is a Certified Registered Nurse Anesthetist provider in Danbury, CT (NPI 1043336258).
Provider details
- NPI number
- 1043336258
- Entity type
- Individual
- Primary specialty
- Certified Registered Nurse AnesthetistPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- A.P.R.N.
- Sex
- Male
- Sole proprietor
- No
- License
- 003588 (CT)
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
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
97 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) |
|---|---|---|
| Anesthesia for Procedure on Nerves, Muscles, Tendons, and Tissue of Forearm, Wrist, and Hand01810 | 48 | $63 |
| Anesthesia for Other Procedure on Forearm, Wrist, Or Hand Bones01830 | 24 | $81 |
| Anesthesia for Open Or Endoscopic Total Shoulder Joint Replacement01638 | 14 | $231 |
| Anesthesia for Total Hip Replacement01214 | 11 | $223 |
Typical Medicare-allowed amounts for these services range $63–$231 (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
- 2007-03-21
- Last updated
- 2007-07-08
Frequently asked questions
- What is John O'Brien's NPI number?
- John O'Brien's National Provider Identifier (NPI) is 1043336258, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is John O'Brien's specialty?
- John O'Brien is listed in the NPPES registry with a primary specialty of Certified Registered Nurse Anesthetist (Physician Assistants & Advanced Practice Nursing Providers).
- Where is John O'Brien located?
- John O'Brien's practice location on file with NPPES is 24 Hospital Ave, Danbury, CT 06810-6099.
- What is John O'Brien's phone number?
- The practice phone number listed in the NPPES registry for John O'Brien is (203) 797-7118.
- Does John O'Brien accept Medicare?
- John 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 John O'Brien's NPI active?
- Yes — John O'Brien's NPI (1043336258) is active in the NPPES registry as of the last update on 2007-07-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.