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Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

DR. THOMAS R SAK PSYD
NPI 1073090239
Clinical Neuropsychologist in Algonquin, IL

Active since July 20, 2018PECOS EnrolledAccepts Medicare Assignment
1451 MERCHANT DR, ALGONQUIN, IL 60102(847) 469-7537(847) 469-7540 Get Directions Write a Review

NPPES record last updated: September 21, 2026. Verified against the NPPES registry weekly; last sync: October 18, 2026.

Record update history: Sep 21, 2026, Nov 20, 2024, Aug 3, 2018 and 1 more (4 updates tracked since 2018).

About Dr. Thomas R Sak Psyd NPPES

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

DR. THOMAS R SAK PSYD (NPI 1073090239) is an individual clinical neuropsychologist in Algonquin, Illinois and active in the NPI registry since July 2018. He is enrolled in Medicare PECOS, maintains 7 additional practice locations, and is a graduate of Other (2016).

NPPES Registry Identity

NPI1073090239
Entity TypeIndividualMale
Primary Taxonomy103G00000X
Provider Legal NameDR. THOMAS R SAKCredential: PSYD
Location Address1451 MERCHANT DRAlgonquin, IL 60102-5917
Mailing Address1451 Merchant DrAlgonquin, IL 60102-5917 · (847) 469-7537 · Fax (847) 469-7540
Phone(847) 469-7537
Fax(847) 469-7540
Sole ProprietorNo
Medical School CMSOtherGraduated 2016
Enumeration DateJuly 20, 2018
Last NPPES UpdateSeptember 21, 20264 updates tracked since enumeration
NPPES CertifiedSeptember 21, 2026
✔ NPI 1073090239 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyClinical NeuropsychologistBehavioral Health & Social Service Providers
Taxonomy Code103G00000X
Definition
A clinical psychologist who applies principles of assessment and intervention based upon the scientific study of human behavior as it relates to normal and abnormal functioning of the central nervous system. The specialty is dedicated to enhancing the understanding of brain-behavior relationships and the application of such knowledge to human problems.
Also ListedPsychologistTaxonomy 103T00000X
1451 MERCHANT DR, Algonquin, IL 60102
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Secondary Practice Locations 7

Location 13701 Commercial Ave Ste 9Northbrook, IL 60062-1830 · Phone (847) 469-7537 · Fax (847) 469-7540
Location 217W662 Butterfield Rd Ste 302Oakbrook Terrace, IL 60181-4006 · Phone (847) 469-7537 · Fax (847) 469-7540
Location 3636 Church St Ste 419Evanston, IL 60201-4580 · Phone (847) 469-7537 · Fax (847) 469-7540
Location 42300 N Barrington Rd Ste 105Hoffman Estates, IL 60169-2033 · Phone (847) 469-7537 · Fax (847) 469-7540
Location 52551 N Clark St Ste 200Chicago, IL 60614-1798 · Phone (847) 469-7537 · Fax (847) 469-7540
Location 62604 Dempster St Ste 407BPark Ridge, IL 60068-8428 · Phone (847) 469-7537 · Fax (847) 469-7540
Location 71531 S Grove Ave Unit 105Barrington, IL 60010-5250 · Phone (847) 469-7537 · Fax (847) 469-7540

Medicare Participation & PECOS CMS

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

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Dr. Thomas R Sak Psyd is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID446771786
PECOS Enrollment IDI20250304000746
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 Thomas Sak reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Thomson Memory Center, PLLC
Same address
Clinical Neuropsychologist
1451 MERCHANT DR
Algonquin, IL 60102
  • Reassigned Medicare billing, Illinois enrollment
  • 14 clinicians in this Medicare group
NPI 1124296082 (847) 469-7537

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 20

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

DR. CHRISTINA JOY BLODGETT PH.D.
Clinical Neuropsychologist
1451 MERCHANT DR
ALGONQUIN, IL 60102
McHenry County (847) 469-7537
ANTONIO MARTINEZ TLATENCHI PH.D.
Clinical Neuropsychologist
1451 MERCHANT DR
ALGONQUIN, IL 60102
McHenry County (847) 469-7537
THOMSON MEMORY CENTER, PLLC
Clinical Neuropsychologist
1451 MERCHANT DR
ALGONQUIN, IL 60102
McHenry County (847) 469-7537
TAYLOR GRECO PSYD
Clinical Neuropsychologist
1451 MERCHANT DR
ALGONQUIN, IL 60102
McHenry County (847) 469-7537
DR. NICKOLAS ARMSTRONG PSY.D.
Clinical Neuropsychologist
1451 MERCHANT DR
ALGONQUIN, IL 60102
McHenry County (847) 469-7537
DR. ARINA POLEVOY PSY.D.
Clinical Neuropsychologist
1451 MERCHANT DR
ALGONQUIN, IL 60102
McHenry County (847) 469-7537
HEATHER PATERSON MA, LPC
Counselor
1451 MERCHANT DR
ALGONQUIN, IL 60102
McHenry County (847) 469-7537
AMANDA SCHNIBBEN-RINGBLOOM PSYD
Psychologist (Clinical)
1451 MERCHANT DR
ALGONQUIN, IL 60102
McHenry County (847) 469-7537

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 Thomas Sak's NPI number?

The NPI number for Thomas Sak is 1073090239. It was assigned to this individual provider in the NPPES registry on July 20, 2018.

Where is Thomas Sak located?

Thomas Sak practices at 1451 Merchant Dr, Algonquin, IL 60102. The listed phone number is (847) 469-7537.

What is Thomas Sak's specialty?

The primary specialty registered for this NPI is Clinical Neuropsychologist with taxonomy code 103G00000X.

Is Thomas Sak enrolled in Medicare?

Yes. Thomas Sak is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

Which organization bills Medicare for Thomas Sak's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Thomas Sak reassigns Medicare benefits to Thomson Memory Center, PLLC (Algonquin, IL). 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 Thomas Sak's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

When was this NPI record last updated?

The NPPES record for Thomas Sak was last updated on September 21, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 29 days 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.