Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. Karen Anne Holbrook, MD, MPH

Infectious Disease Physician in Sebastopol, CA · enumerated 2006.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1235211954

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Registry record

Entity type Individual (Type 1)

Name Dr. Karen Anne Holbrook

Credential MD, MPH

Sex Female

Practice address Sebastopol, CA, 95472

Phone (707) 889-9649

Enumeration date Oct 20, 2006

Last updated in NPPES Mar 17, 2021

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

207RI0200X Infectious Disease Physician Allopathic & Osteopathic Physicians · License G84580 (CA) Primary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

What is the NPI number for Karen Holbrook?

The National Provider Identifier (NPI) for Karen Holbrook is 1235211954, a Type 1 (individual) record in the CMS NPPES registry.

Where does Karen Holbrook practice?

The practice location on file with NPPES is in Sebastopol, CA. Providers can have multiple locations; NPPES lists the primary practice address.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2021-03-17.