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MERRIMACK VALLEY INTERNAL MEDICINE LTC
NPI 1134054547
Internal Medicine in Bedford, MA

Active since June 16, 2026CLIA 22D0979424 · Waiver
22 WEBBER AVE, BEDFORD, MA 01730(978) 430-2975 Get Directions Write a Review

NPPES record last updated: August 4, 2026. Verified against the NPPES registry weekly; last sync: November 08, 2026.

Record update history: Aug 4, 2026, Jul 23, 2026 (2 updates tracked since 2026).

About Merrimack Valley Internal Medicine Ltc NPPES

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

MERRIMACK VALLEY INTERNAL MEDICINE LTC (NPI 1134054547) is a healthcare organization registered as an internal medicine in Bedford, Massachusetts and active in the NPI registry since June 2026. The organization holds a CLIA Waiver certificate valid through October 22, 2028 and lists Michael G Bertos, Owner, as its authorized official.

NPPES Registry Identity

NPI1134054547
Entity TypeOrganization
Primary Taxonomy207R00000X
Legal Business NameMERRIMACK VALLEY INTERNAL MEDICINE LTC
Location Address22 WEBBER AVEBedford, MA 01730-2213
Mailing Address22 Webber AveBedford, MA 01730-2213
Phone(978) 430-2975
Organization SubpartNo
Authorized OfficialMichael G BertosOwner · (978) 459-2152
Enumeration DateJune 16, 2026
Last NPPES UpdateAugust 4, 20262 updates tracked since enumeration
NPPES CertifiedAugust 4, 2026
✔ NPI 1134054547 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207R00000X
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.
22 WEBBER AVE, Bedford, MA 01730
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Group Practice 1

Group TaxonomyThis provider is a business group of one or more individual practitioners, who practice with different areas of specialization.193200000X MULTI-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)

Merrimack Valley Internal Medicine Ltc is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Clinicians Billing Medicare Through This Organization

5

Medicare enrollment records show 5 clinicians reassign Medicare billing to Merrimack Valley Internal Medicine Ltc, which bills Medicare for the services they deliver. They are listed nearest first.

Clinicians, nearest first (5)

Louis Bresnick, M.D.
Internal Medicine
NPI 1205861390
20 RESEARCH PL SUITE 310
N Chelmsford, MA 01863
(978) 459-2152
✔ PECOS✔ Accepts Medicare11 mi
Jayme Cerullo, NP
Nurse Practitioner
NPI 1689711871
20 RESEARCH PL SUITE 310
N Chelmsford, MA 01863
(978) 459-2152
✔ PECOS✔ Accepts Medicare11 mi
Susan Jamieson, NP
Nurse Practitioner
NPI 1245306448
20 RESEARCH PL STE 310
North Chelmsford, MA 01863
(617) 782-7788
✔ PECOS✔ Accepts Medicare11 mi
Michael Bertos, M.D.
Internal Medicine
NPI 1043245145
20 RESEARCH PL SUITE 310
N Chelmsford, MA 01863
(978) 459-2152
✔ PECOS✔ Accepts Medicare11 mi
Teresa Gore, ANP-BC
Nurse Practitioner
NPI 1013243138
11 NEVINS ST SUITE 401
Brighton, MA 02135
(617) 782-7788
✔ PECOS✔ Accepts Medicare12 mi

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 of Waiver 22D0979424

Merrimack Valley Internal Medicine Associates PC · North Chelmsford, MA
Active · expires Oct 22, 2028
CLIA Number22D0979424
Laboratory TypePhysician Office
Certificate Effective DateOctober 23, 2026
Certificate Expiration DateOctober 22, 2028
Laboratory DirectorLouis Bresnick
Laboratory Phone(978) 459-2152
Laboratory LocationMerrimack Valley Internal Medicine Associates PC20 Research Place Suite 310, North Chelmsford, MA 01863
CLIA data matches this NPI record on: Phone
This certificate is issued to a laboratory to perform only 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 Merrimack Valley Internal Medicine Ltc's NPI number?

The NPI number for Merrimack Valley Internal Medicine Ltc is 1134054547. It was assigned to this organization in the NPPES registry on June 16, 2026.

Where is Merrimack Valley Internal Medicine Ltc located?

Merrimack Valley Internal Medicine Ltc is located at 22 Webber Ave, Bedford, MA 01730. The listed phone number is (978) 430-2975.

What is Merrimack Valley Internal Medicine Ltc's specialty?

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

Is Merrimack Valley Internal Medicine Ltc enrolled in Medicare?

Yes. Merrimack Valley Internal Medicine Ltc is registered in the Medicare PECOS enrollment system.

How many clinicians bill Medicare through Merrimack Valley Internal Medicine Ltc?

According to the CMS Revalidation Reassignment List (October 2026 release), 5 clinicians in 2 Medicare specialties reassign their Medicare billing to Merrimack Valley Internal Medicine Ltc. 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. The largest specialties are Nurse Practitioner (3) and Internal Medicine (2). Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Does Merrimack Valley Internal Medicine Ltc hold a CLIA laboratory certificate?

Yes. A Certificate of Waiver (number 22D0979424) is associated with this NPI, valid through October 22, 2028. CLIA certificates authorize laboratory testing under the federal Clinical Laboratory Improvement Amendments program.

When was this NPI record last updated?

The NPPES record for Merrimack Valley Internal Medicine Ltc was last updated on August 4, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 3 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.