Margaret O'Brien, R.D.
NPI 1659331536 · Registered Dietitian · Phoenix, AZ
Enrolled with Medicare as Practitioner - Registered Dietitian Or Nutrition Professional · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Margaret O'Brien, R.D. is a Registered Dietitian provider in Phoenix, AZ (NPI 1659331536).
Provider details
- NPI number
- 1659331536
- Entity type
- Individual
- Primary specialty
- Registered DietitianDietary & Nutritional Service Providers
- Credential
- R.D.
- Sex
- Female
- Sole proprietor
- No
- License
- 554938 (AZ)
Specialties & taxonomies
Dietary & Nutritional Service Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
20 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
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.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-03-24
- Last updated
- 2018-11-08
Frequently asked questions
- What is Margaret O'Brien's NPI number?
- Margaret O'Brien's National Provider Identifier (NPI) is 1659331536, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Margaret O'Brien's specialty?
- Margaret O'Brien is listed in the NPPES registry with a primary specialty of Registered Dietitian (Dietary & Nutritional Service Providers).
- Where is Margaret O'Brien located?
- Margaret O'Brien's practice location on file with NPPES is 1441 N 12th St Fl 2, Phoenix, AZ 85006-2837.
- What is Margaret O'Brien's phone number?
- The practice phone number listed in the NPPES registry for Margaret O'Brien is (602) 521-5200.
- Does Margaret O'Brien accept Medicare?
- Margaret 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 Margaret O'Brien's NPI active?
- Yes — Margaret O'Brien's NPI (1659331536) is active in the NPPES registry as of the last update on 2018-11-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.