2026 NPPES data Family Medicine Physician NPI 1003854274 D.O.
Verify on CMS →

STEPHEN THACKER, D.O.

Family Medicine Physician in BREA, California. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.

What the federal data shows

STEPHEN THACKER, D.O. is a Family Medicine Physician in BREA, California, listed in the federal CMS National Provider Identifier registry.

Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) — no proprietary rating or editorial opinion is applied.

Board-eligible specialty (heuristic — not verified)

STEPHEN THACKER, D.O. practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about STEPHEN THACKER, D.O.?

Quality data not reported

NPI registry status

Active

Issued 06/02/2006

NPI 1003854274

Primary specialty

Family Medicine Physician

High-volume

147,640 US NPIs in this specialty

Specialty distribution in California

How Family Medicine Physician compares to other specialties among California providers

California providers

Family Medicine Physician share within California

1. Family Medicine Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Family Medicine Physician share within California

Specialty board-certification context

Estimated specialty board-certified rate — Family Medicine Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Family Medicine Physician ABMS/AOA estimate

Est. board-certified rate (Family Medicine Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Family Medicine Physician) — ABMS / AOA estimate

The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.

Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).

STEPHEN THACKER, D.O. appears in the CMS NPPES registry as a Family Medicine Physician provider holding D.O. credentials at 340 W CENTRAL AVE STE 110, BREA, CA, 92821, with a listed phone of (714) 529-3971. NPI 1003854274 was issued on 06/02/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what THACKER most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D prescribing data is not currently published for this NPI, which typically means the provider either wrote fewer than 11 Part D claims in the most recent reporting year, does not participate in Medicare, or practices in a specialty that rarely prescribes outpatient drugs. Absence of prescribing data is not a quality signal — many Family Medicine Physician providers operate outside Part D entirely.

Family Medicine Physician is a high-volume specialty nationwide, with 147,640 enrolled providers across 56 states and an average of 3,418 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline. Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist — always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.

Practice Address

340 W CENTRAL AVE STE 110
BREA, CA 92821

Provider Details

NPI 1003854274
Specialty Family Medicine Physician
Credentials D.O.
Gender Male
NPI Issued 06/02/2006

License & disciplinary context — California MBC 2023 annual report

Aggregate state board data only — NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 — they are NOT specific to STEPHEN THACKER, D.O.. To verify STEPHEN THACKER, D.O.'s current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases

MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Family Medicine Physician Overview

How STEPHEN THACKER, D.O. fits within the Family Medicine Physician landscape nationally.

147,640
Family Medicine Physician Providers in US
56
States with Family Medicine Physician
3,418
Avg Claims per Provider

Nearby Family Medicine Physician Providers in California

Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as THACKER.

Compare Family Medicine Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is STEPHEN THACKER, D.O.'s specialty?
STEPHEN THACKER, D.O. specializes in Family Medicine Physician and practices in BREA, California. Credentials: D.O..
Where is STEPHEN THACKER, D.O. located?
STEPHEN THACKER, D.O. is located at 340 W CENTRAL AVE STE 110, BREA, CA, 92821. Phone: (714) 529-3971.
What is STEPHEN THACKER, D.O.'s NPI number?
STEPHEN THACKER, D.O.'s National Provider Identifier (NPI) is 1003854274, issued on 06/02/2006.
How many Family Medicine Physician providers are there in the US?
There are 147,640 Family Medicine Physician providers across 56 states in the US. The average Family Medicine Physician provider writes 3,418 Medicare Part D claims per year.
Does STEPHEN THACKER, D.O. accept Medicare?
STEPHEN THACKER, D.O. appears in CMS Medicare data. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify STEPHEN THACKER, D.O.'s credentials?
STEPHEN THACKER, D.O.'s NPI is 1003854274 with credentials D.O.. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.

Data Sources

Provider Directory
CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
Specialty Classification
NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
Limitations
Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.

See our complete data methodology for details on how we collect and process government data.

Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).

Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology