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Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

DR. ALLAN DOUGLAS SIEFKIN MD
NPI 1033113758
Internal Medicine in Sacramento, CA

Active since June 09, 2005
2315 STOCKTON BLVD, SACRAMENTO, CA 95817(916) 734-1166(916) 734-3234 Get Directions Write a Review

NPPES record last updated: July 13, 2026. Verified against the NPPES registry weekly; last sync: August 02, 2026.

Record update history: Jul 13, 2026, Sep 11, 2025 (2 updates tracked since 2025).

About Dr. Allan Douglas Siefkin Md NPPES

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

DR. ALLAN DOUGLAS SIEFKIN MD (NPI 1033113758) is an individual internal medicine provider in Sacramento, California, licensed in California (G032410) and active in the NPI registry since June 2005.

NPPES Registry Identity

NPI1033113758
Entity TypeIndividualMale
Primary Taxonomy207R00000X
Provider Legal NameDR. ALLAN DOUGLAS SIEFKINCredential: MD
Location Address2315 STOCKTON BLVDSacramento, CA 95817-2201
Mailing Address2315 Stockton BlvdSacramento, CA 95817-2201 · (916) 734-1166 · Fax (916) 734-3234
Phone(916) 734-1166
Fax(916) 734-3234
Sole ProprietorNo
Enumeration DateJune 9, 2005
Last NPPES UpdateJuly 13, 20262 updates tracked since enumeration
✔ NPI 1033113758 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 3

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207R00000X
License✔ Licensed in CA · G032410
Definition
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
Also ListedInternal Medicine · Critical Care MedicineTaxonomy 207RC0200X · License G032410 (CA)
Also ListedInternal Medicine · Pulmonary DiseaseTaxonomy 207RP1001X · License G032410 (CA)
2315 STOCKTON BLVD, Sacramento, CA 95817
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Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

KATHLEEN STUCKER
Social Worker (Clinical)
2315 STOCKTON BLVD
SACRAMENTO, CA 95817
Sacramento County (916) 734-5628
MARIA ISABEL AGUILAR
Registered Nurse
2315 STOCKTON BLVD
SACRAMENTO, CA 95817
Sacramento County (916) 734-8730
NATHAN JACOB VANDEN BERGE
Emergency Medicine
2315 STOCKTON BLVD
SACRAMENTO, CA 95817
Sacramento County (916) 734-8570
PETER SANTIAGO C.O., C.PED., FAAOP
Specialist
2315 STOCKTON BLVD
SACRAMENTO, CA 95817
Sacramento County (916) 734-7045
SHIELA LEIGH SAMSON ANGULO DO
Student in an Organized Health Care Education/Training Program
2315 STOCKTON BLVD
SACRAMENTO, CA 95817
Sacramento County (916) 734-5974
MS. KATHLEEN DOLORES VAN LEEUWEN MD
Surgery (Pediatric Surgery)
2315 STOCKTON BLVD
SACRAMENTO, CA 95817
Sacramento County (916) 734-3229
STEPHEN MULFORD
Physical Therapy Assistant
2315 STOCKTON BLVD, ROOM 0512
SACRAMENTO, CA 95817
Sacramento County (916) 734-7248
MR. MARK YAMADA
Occupational Therapist
2315 STOCKTON BLVD
SACRAMENTO, CA 95817
Sacramento County (916) 734-7248

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 Allan Siefkin's NPI number?

The NPI number for Allan Siefkin is 1033113758. It was assigned to this individual provider in the NPPES registry on June 9, 2005.

Where is Allan Siefkin located?

Allan Siefkin practices at 2315 Stockton Blvd, Sacramento, CA 95817. The listed phone number is (916) 734-1166.

What is Allan Siefkin's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

When was this NPI record last updated?

The NPPES record for Allan Siefkin was last updated on July 13, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 25 days 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.