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Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Mr. Mark Allen Messerer, SUDCC

Addiction (Substance Use Disorder) Counselor in Martinez, CA · enumerated 2006.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1790841682

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Registry record

Entity type Individual (Type 1)
Name Mr. Mark Allen Messerer
Credential SUDCC
Sex Male
Practice address Martinez, CA, 94553
Phone (925) 335-3330
Enumeration date Dec 28, 2006
Last updated in NPPES Mar 27, 2023

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

101YA0400X Addiction (Substance Use Disorder) Counselor Behavioral Health & Social Service Providers Secondary
101YA0400X Addiction (Substance Use Disorder) Counselor Behavioral Health & Social Service Providers · License M0102271028 (CA) Primary

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

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Frequently asked questions

How do I verify Mark Messerer's NPI record?
Cross-check NPI 1790841682 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.
Is NPI 1790841682 active?
Yes, as of the latest NPPES snapshot, NPI 1790841682 is active (record last updated 2023-03-27).

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-03-27.