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Walter Prehn, MD
NPI 1225042088 · Internal Medicine Physician · Sonoma, CA
Walter Prehn, MD is a Internal Medicine Physician provider in Sonoma, CA (NPI 1225042088).
Provider details
- NPI number
- 1225042088
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- Yes
- License
- G254540 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
Detailed profile(91/100 index)
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
19 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
181 Andrieux Street
Suite 206
Sonoma, CA 95476-6920
Phone: (707) 495-7762
Fax: (707) 938-7337
Street-level locationGet directions
Mailing address
181 Andrieux Street
Sonoma, CA 95476-6920
Registry dates
- Enumerated
- 2006-07-28
- Last updated
- 2012-09-25
Frequently asked questions
- What is Walter Prehn's NPI number?
- Walter Prehn's National Provider Identifier (NPI) is 1225042088, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Walter Prehn's specialty?
- Walter Prehn is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Walter Prehn located?
- Walter Prehn's practice location on file with NPPES is 181 Andrieux Street, Sonoma, CA 95476-6920.
- What is Walter Prehn's phone number?
- The practice phone number listed in the NPPES registry for Walter Prehn is (707) 495-7762.
- Is Walter Prehn's NPI active?
- Yes — Walter Prehn's NPI (1225042088) is active in the NPPES registry as of the last update on 2012-09-25.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.