Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor
Dr. David Glenn Markwell, PHD, LPC, NCC
Professional Counselor in Marietta, GA · enumerated 2006.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1336173541
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Registry record
Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.
Taxonomy & licenses
Other identifiers
| Identifier | Type | State | Issuer |
|---|---|---|---|
| 201137 | Other | GA | BLUE CROSS BLUE SHIELD |
| 2013 | Other | - | TRICARE |
| 376933122C | Medicaid | GA | - |
| 285087495 | Other | - | UNITED BEHAVORIAL |
| 477177000 | Other | GA | MAGELLAN |
| 7007423 | Other | GA | AETNA |
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.
Frequently asked questions
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Other providers at this practice address
Browse all →Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2025-12-12.