LAKE FOREST INTERNAL MEDICINE, LTD
NPI 1871786731
Internal Medicine in Libertyville, IL

Q: What is Lake Forest Internal Medicine, Ltd's NPI number?

The NPI number for Lake Forest Internal Medicine, Ltd is 1871786731. It was assigned to this organization in the NPPES registry on August 23, 2007.

Q: What is Lake Forest Internal Medicine, Ltd's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Active since August 23, 2007CLIA 14D0993499 · Microscopy

1800 HOLLISTER DR, STE 211, LIBERTYVILLE, IL 60048(847) 816-3084(847) 816-0031 Get Directions Write a Review

NPPES record last updated: October 24, 2012. Verified against the NPPES registry weekly; last sync: October 18, 2026.

On this page

About Lake Forest Internal Medicine, Ltd NPPES

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

LAKE FOREST INTERNAL MEDICINE, LTD (NPI 1871786731) is a healthcare organization registered as an internal medicine in Libertyville, Illinois and active in the NPI registry since August 2007. The organization holds a CLIA Microscopy certificate valid through November 14, 2027 and lists Elliot F Miller, Vice President/ Treasurer, as its authorized official.

NPPES Registry Identity

NPI1871786731

Entity TypeOrganization

Primary Taxonomy207R00000X

Legal Business NameLAKE FOREST INTERNAL MEDICINE, LTD

Location Address1800 HOLLISTER DR, STE 211Libertyville, IL 60048-5263

Mailing Address1800 Hollister Dr, Ste 211Libertyville, IL 60048-5263 · (847) 816-3084 · Fax (847) 816-0031

Phone(847) 816-3084

Fax(847) 816-0031

Organization SubpartNo

Authorized OfficialElliot F MillerVice President/ Treasurer · (847) 816-3084

Enumeration DateAugust 23, 2007

Last NPPES UpdateOctober 24, 2012

✔ NPI 1871786731 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians

Taxonomy Code207R00000X

License✔ Licensed in IL · 042617582

Definition

A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.

1800 HOLLISTER DR, Libertyville, IL 60048

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Group Practice 1

Group TaxonomyThis provdier is a business group of one or more individual practitioners, all of who practice with the same area of specialization.193400000X SINGLE SPECIALTY GROUP

Medicare Participation & PECOS CMS

Medicare enrollment and the clinicians who bill Medicare through this organization, from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Lake Forest Internal Medicine, Ltd is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Clinicians Billing Medicare Through This Organization

Medicare enrollment records show 2 clinicians reassign Medicare billing to Lake Forest Internal Medicine, Ltd, which bills Medicare for the services they deliver. Of these, 2 practice at this address. They are listed nearest first.

Clinicians, nearest first (2)

Elliot Miller, MD

Internal Medicine

NPI 1164441572

1800 HOLLISTER DR
Libertyville, IL 60048

(847) 816-3084

✔ PECOS✔ Accepts MedicareSame address

Mark Riederman, M.D.

Internal Medicine

NPI 1699782151

1800 HOLLISTER DR SUITE 211
Libertyville, IL 60048

(847) 816-3084

✔ PECOS✔ Accepts MedicareSame address

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

CLIA Laboratory Certificates CMS CLIA

Laboratory certificates issued under the Clinical Laboratory Improvement Amendments (CLIA) program, which sets federal quality standards for human laboratory testing in the United States. There is no official CMS crosswalk between CLIA and NPI numbers; these certificates are associated with this NPI by matching facility names, locations and phone numbers in the CMS CLIA registry.

Certificate for Provider-Performed Microscopy Procedures (PPMP) 14D0993499

Lake Forest Internal Medicine · Libertyville, IL

Active · expires Nov 14, 2027

CLIA Number14D0993499

Laboratory TypePhysician Office

Certificate Effective DateNovember 15, 2025

Certificate Expiration DateNovember 14, 2027

Laboratory DirectorMark W. Riederman MD

Laboratory Phone(847) 816-3084

Laboratory LocationLake Forest Internal Medicine1800 Hollister Drive Suite 211, Libertyville, IL 60048

CLIA data matches this NPI record on: Address Name Phone

This certificate is issued to a laboratory in which a physician, midlevel practitioner or dentist performs no tests other than the microscopy procedures. This certificate permits the laboratory to also perform waived tests.

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 Lake Forest Internal Medicine, Ltd's NPI number?

The NPI number for Lake Forest Internal Medicine, Ltd is 1871786731. It was assigned to this organization in the NPPES registry on August 23, 2007.

Where is Lake Forest Internal Medicine, Ltd located?

Lake Forest Internal Medicine, Ltd is located at 1800 Hollister Dr Ste 211, Libertyville, IL 60048. The listed phone number is (847) 816-3084.

What is Lake Forest Internal Medicine, Ltd's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Is Lake Forest Internal Medicine, Ltd enrolled in Medicare?

Yes. Lake Forest Internal Medicine, Ltd is registered in the Medicare PECOS enrollment system.

How many clinicians bill Medicare through Lake Forest Internal Medicine, Ltd?

According to the CMS Revalidation Reassignment List (October 2026 release), 2 clinicians, all in Internal Medicine, reassign their Medicare billing to Lake Forest Internal Medicine, Ltd. A 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 the clinician's services. Of these, 2 practice at this address. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Does Lake Forest Internal Medicine, Ltd hold a CLIA laboratory certificate?

Yes. A Certificate for Provider-Performed Microscopy Procedures (PPMP) (number 14D0993499) is associated with this NPI, valid through November 14, 2027. CLIA certificates authorize laboratory testing under the federal Clinical Laboratory Improvement Amendments program.

When was this NPI record last updated?

The NPPES record for Lake Forest Internal Medicine, Ltd was last updated on October 24, 2012. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 14 years 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.