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AMAST MEDICAL ASSOCIATES, PC
NPI 1184519241
Psychiatry & Neurology - Psychiatry in San Francisco, CA

Active since June 10, 2025
166 GEARY ST, STE 1500 #1717, SAN FRANCISCO, CA 94108(415) 745-2855 Get Directions Write a Review

NPPES record last updated: December 6, 2025. Verified against the NPPES registry weekly; last sync: October 18, 2026.

Record update history: Dec 6, 2025, Jun 10, 2025 (2 updates tracked since 2025).

About Amast Medical Associates, Pc NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

AMAST MEDICAL ASSOCIATES, PC (NPI 1184519241), doing business as Amast Medical Associates, is a healthcare organization registered as a psychiatry in San Francisco, California and active in the NPI registry since June 2025. The organization lists Jack Hale Buchanan, Co-owner & Physician, as its authorized official.

NPPES Registry Identity

NPI1184519241
Entity TypeOrganization
Primary Taxonomy2084P0800X
Legal Business NameAMAST MEDICAL ASSOCIATES, PC
Location Address166 GEARY ST, STE 1500 #1717San Francisco, CA 94108-5628
Mailing Address166 Geary St, Ste 1500 #1717San Francisco, CA 94108-5628 · (415) 745-2855
Phone(415) 745-2855
Organization SubpartNo
Authorized OfficialJack Hale BuchananCo-owner & Physician · (415) 745-2855
Enumeration DateJune 10, 2025
Last NPPES UpdateDecember 6, 20252 updates tracked since enumeration
NPPES CertifiedDecember 6, 2025
✔ NPI 1184519241 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyPsychiatry & Neurology · PsychiatryAllopathic & Osteopathic Physicians
Taxonomy Code2084P0800X
Definition
A Psychiatrist specializes in the prevention, diagnosis, and treatment of mental disorders, emotional disorders, psychotic disorders, mood disorders, anxiety disorders, substance-related disorders, sexual and gender identity disorders and adjustment disorders. Biologic, psychological, and social components of illnesses are explored and understood in treatment of the whole person. Tools used may include diagnostic laboratory tests, prescribed medications, evaluation and treatment of psychological and interpersonal problems with individuals and families, and intervention for coping with stress, crises, and other problems.
166 GEARY ST, San Francisco, CA 94108
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Other Names 1

Doing Business AsAmast Medical Associates

Group Practice 1

Group TaxonomyThis provider is a business group of one or more individual practitioners, who practice with different areas of specialization.193200000X MULTI-SPECIALTY GROUP

Medicare Participation & PECOS CMS

Medicare enrollment and the clinicians who bill Medicare through this organization, from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Amast Medical Associates, Pc is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Clinicians Billing Medicare Through This Organization

2

Medicare enrollment records show 2 clinicians reassign Medicare billing to Amast Medical Associates, PC, which bills Medicare for the services they deliver. Of these, 1 practice within 10 miles. They are listed nearest first.

Clinicians, nearest first (2)

Jack Buchanan, MD, PHD
Psychiatry
NPI 1093343014
1001 POTRERO AVE BLDG 5
San Francisco, CA 94110
(628) 206-8125
✔ PECOS✔ Accepts Medicare2.2 mi
Michael Dinh
Psychiatry
NPI 1356978639
401 QUARRY RD
Palo Alto, CA 94304
(415) 683-0703
✔ PECOS✔ Accepts Medicare27 mi

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Amast Medical Associates, PC's NPI number?

The NPI number for Amast Medical Associates, PC is 1184519241. It was assigned to this organization in the NPPES registry on June 10, 2025. The provider is doing business as Amast Medical Associates.

Where is Amast Medical Associates, PC located?

Amast Medical Associates, PC is located at 166 Geary St Ste 1500 #1717, San Francisco, CA 94108. The listed phone number is (415) 745-2855.

What is Amast Medical Associates, PC's specialty?

The primary specialty registered for this NPI is Psychiatry & Neurology, specializing in Psychiatry, with taxonomy code 2084P0800X.

Is Amast Medical Associates, PC enrolled in Medicare?

Yes. Amast Medical Associates, PC is registered in the Medicare PECOS enrollment system.

How many clinicians bill Medicare through Amast Medical Associates, PC?

According to the CMS Revalidation Reassignment List (October 2026 release), 2 clinicians, all in Psychiatry, reassign their Medicare billing to Amast Medical Associates, PC. A reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for the clinician's services. Of these, 1 practice within 10 miles. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

When was this NPI record last updated?

The NPPES record for Amast Medical Associates, PC was last updated on December 6, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.