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DR. DAVID GLENN MARKWELL PHD, LPC, NCC
NPI 1336173541
Counselor - Professional in Marietta, GA

Active since July 11, 2006PECOS Enrolled
2440 SANDY PLAINS ROAD, BUILDING 21 SUITE 200, MARIETTA, GA 30066(770) 993-9700(770) 993-9800 Get Directions Write a Review

NPPES record last updated: December 12, 2025. Verified against the NPPES registry weekly; last sync: October 18, 2026.

Record update history: Dec 12, 2025, Feb 23, 2022 (2 updates tracked since 2022).

About Dr. David Glenn Markwell Phd, Lpc, Ncc NPPES

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

DR. DAVID GLENN MARKWELL PHD, LPC, NCC (NPI 1336173541) is an individual professional provider in Marietta, Georgia, licensed in Georgia (3565) and active in the NPI registry since July 2006. He is enrolled in Medicare PECOS.

NPPES Registry Identity

NPI1336173541
Entity TypeIndividualMale
Primary Taxonomy101YP2500X
Provider Legal NameDR. DAVID GLENN MARKWELLCredential: PHD, LPC, NCC
Location Address2440 SANDY PLAINS ROAD, BUILDING 21 SUITE 200Marietta, GA 30066-7233
Mailing Address2440 Sandy Plains Road, Building 21 Suite 200Marietta, GA 30066-7233 · (770) 993-9700 · Fax (770) 993-9800
Phone(770) 993-9700
Fax(770) 993-9800
Sole ProprietorYes
Enumeration DateJuly 11, 2006
Last NPPES UpdateDecember 12, 20252 updates tracked since enumeration
NPPES CertifiedDecember 12, 2025
✔ NPI 1336173541 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyCounselor · ProfessionalBehavioral Health & Social Service Providers
Taxonomy Code101YP2500X
License✔ Licensed in GA · 3565
2440 SANDY PLAINS ROAD, Marietta, GA 30066
Open in Google Maps ↗

Other Identifiers 6

Other201137GA · Blue Cross Blue Shield
Other2013Tricare
Medicaid376933122CGA
Other285087495United Behavorial
Other477177000GA · Magellan
Other7007423GA · Aetna

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Alliant Health Plans, Inc., Ambetter from Absolute Total Care, Ambetter Health and more.Insurance ›

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Dr. David Glenn Markwell Phd, Lpc, Ncc is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment– Home Health Agency– Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignment

Medicare enrollment records show David Markwell reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Ridgeline Counseling LLC
Same address
Community/Behavioral Health
2440 SANDY PLAINS ROAD, BUILDING 21 SUITE 200
Marietta, GA 30066
  • Reassigned Medicare billing, Georgia enrollment
NPI 1508058389 (770) 993-9700

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Other Providers at the Same Location NPPES 3

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

RIDGELINE COUNSELING LLC
Community/Behavioral Health
2440 SANDY PLAINS ROAD, BUILDING 21 SUITE 200
MARIETTA, GA 30066
Cobb County (770) 993-9700
COMFORT COMMUNITY CENTER, LLC
Skilled Nursing Facility (Nursing Care, Pediatric)
2440 SANDY PLAINS ROAD, BLVD 21, SUITE 100
MARIETTA, GA 30066
Cobb County (678) 401-8743
CLEARBROOK COUNSELING LLC
Community/Behavioral Health
2440 SANDY PLAINS ROAD, BUILDING 21 SUITE 200
MARIETTA, GA 30066
Cobb County (770) 993-9700

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 David Markwell's NPI number?

The NPI number for David Markwell is 1336173541. It was assigned to this individual provider in the NPPES registry on July 11, 2006.

Where is David Markwell located?

David Markwell practices at 2440 Sandy Plains Road Building 21 Suite 200, Marietta, GA 30066. The listed phone number is (770) 993-9700.

What is David Markwell's specialty?

The primary specialty registered for this NPI is Counselor, specializing in Professional, with taxonomy code 101YP2500X.

Is David Markwell enrolled in Medicare?

Yes. David Markwell is registered in the Medicare PECOS enrollment system.

Which organization bills Medicare for David Markwell's services?

According to the CMS Revalidation Reassignment List (October 2026 release), David Markwell reassigns Medicare benefits to Ridgeline Counseling LLC (Marietta, GA). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for David Markwell's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

What insurance does David Markwell accept?

Health plans from Alliant Health Plans, Inc., Ambetter Health, Ambetter from Absolute Total Care, Ambetter of Alabama and Ambetter of North Carolina and 4 other insurers list David Markwell as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.

When was this NPI record last updated?

The NPPES record for David Markwell was last updated on December 12, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 months 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.