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

Warren Joseph A San Diego, MD

Individual provider Internal Medicine Physician · NPI 1083036743

Warren Joseph A San Diego, MD practises Internal Medicine in Fairfield, California. Qualified in 2011, 15 years ago. Practices with Northbay Physicians Surgery Center, LLC, a 337-clinician group and accepts Medicare assignment. Licensed in California.

Years since qualifying
15
Licensed in
CA
In the registry since
2014
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

1200 B Gale Wilson Blvd
Fairfield, CA 94533-3552
Phone: (707) 646-5080
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Internal Medicine Physician (primary) Taxonomy 207R00000X · Licence A130099 (CA)

Record details

NPI number1083036743
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJanuary 15, 2014
Last updated in NPPESJuly 22, 2019

Medicare enrollment

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

Medicare specialtyINTERNAL MEDICINE
Medical schoolOTHER
Graduated 2011 (15 years in practice)
Group practice Northbay Physicians Surgery Center, Llc — 337 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

Procedures

From CMS Care Compare, which counts the procedures a clinician billed to Original Medicare and Medicare Advantage over a recent 12-month period. CMS reports a fixed list of common procedures, so this is not everything the clinician does. Counts of 10 or fewer are given as a range, because CMS withholds small numbers.

Removal of tissue 1–10 times

The percentile compares how often this clinician performed the procedure with other clinicians who performed it, as CMS calculates it. It measures volume, not outcomes or skill.

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients331
Services billed 874 a service is one billed item, such as a visit, a test or a procedure
Average patient age76

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

Colleagues at Northbay Physicians Surgery Center, LLC

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 337 clinicians in the practice; 12 are shown here.

Other providers in Fairfield