Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
NPIDirectory

Alexander William Threlfall, MD

Individual provider Psychiatry Physician · NPI 1669538187

Alexander William Threlfall, MD is a Psychiatry in Greenbrae, California. Qualified in 2006, 20 years ago. Practices with Regents Univ of California UCSF, a 272-clinician group, works from 3 locations and offers telehealth. Licensed in California.

Years since qualifying
20
Licensed in
CA
In the registry since
2006
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

250 Bon Air Rd
Greenbrae, CA 94904-1702
Phone: (415) 925-7618
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (2)

  • 5789 State Farm Dr Ste 110, Rohnert Park, CA 94928-6308 — (707) 615-4437
  • 3569 Round Barn Cir, Santa Rosa, CA 95403-5781 — (707) 303-3600

Specialties & licences

Psychiatry Physician (primary) Taxonomy 2084P0800X · Licence 113086 (CA)

Record details

NPI number1669538187
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedDecember 29, 2006
Last updated in NPPESOctober 29, 2025
Certification dateOctober 29, 2025

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyPSYCHIATRY
Also practisesGERIATRIC PSYCHIATRY
Medical schoolOTHER
Graduated 2006 (20 years in practice)
Group practice Regents Univ Of California Ucsf — 272 clinicians
Accepts Medicare assignment Not indicated
TelehealthOffers telehealth services
Practice locations2 on file with Medicare

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