Nephrology Associates of the Merrimack Valley

Nephrology • Taunton, MA • Multiple (Lowell, Chelmsford, Methuen) locations

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About

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Clinic Type

Nephrology

Address

Lowell, Chelmsford, and Methuen, MA (serving Merrimack Valley)

Phone

978-453-1811

Email

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Opening Hours

Not published — contact the clinic to confirm hours.

Website

https://www.nephrologydoctors.net/

Services Offered

Kidney disease treatment
Hypertension care
Kidney stone prevention
Pre-dialysis care
Post-transplant care
Chronic kidney disease management
In-center dialysis
Home dialysis
Dialysis facility medical direction

Team

Douglas E. Mesler, MD, MPH, Internal Medicine and Nephrology; formerly Clinical Director for Nephrology at Boston Medical Center; moved practice to Lowell in 2005 — Physician / Medical Director
Joseph P. Rossacci, MD, Internal Medicine; Nephrology fellowship at Beth Israel Deaconess Medical Center; member since 2007 — Physician / Medical Director (Fresenius Chelmsford dialysis facility)
Ashish Mahajan, MD, MPH, MS, Residency at St. Elizabeth’s Hospital; Nephrology fellowship at Tufts Medical Center; member since 2007 — Physician

Insurance & Payment

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Languages Spoken

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FAQs

What conditions do you treat?

All types of acute and chronic kidney disease, hypertension, kidney stone prevention, pre-dialysis, and post-transplant.

Where do you provide care?

Patients receiving chronic in-center and home dialysis in Lowell, Chelmsford, and Methuen.

What types of kidney disease do you care for?

We care for all types of acute and chronic kidney disease, hypertension, kidney stone prevention, pre-dialysis, and post-transplant.

Do you treat patients on dialysis?

We see patients receiving chronic in-center and home dialysis in Lowell, Chelmsford, and Methuen.

Where are your facilities located?

Locations include Lowell, Chelmsford, and Methuen in the Merrimack Valley.

Who are the physicians and what are their credentials?

Physicians include Douglas E. Mesler, MD, MPH; Joseph P. Rossacci, MD; Ashish Mahajan, MD, MPH, MS, with internal medicine and nephrology certification. (More bios available on site.)

Photos

What Patients Say

Overall sentiment across review platforms: positive

Healthgrades (Dr. Tatiana Thom, MD): 5.0 star rating (9 reviews (7 with written review))
Southcoast Health (Ye Tun, MD): 4.9 (227 ratings (51 patient comments))
Sharecare (Dr. Tatiana Thom, MD): 5.0/5 (1 review)

Patients praise

Doctors who listen thoroughly and spend time with patients
Clear explanations of conditions, labs, and treatment options
Attentive, friendly staff and good office experiences
Convenience elements reported (e.g., telehealth options, scheduling ease, short wait times)

Common complaints

No specific negative complaints were captured in the provided results (mostly favorable review excerpts).

"“She combine[s] deep medical knowledge with a kind and reassuring manner that makes you feel completely at ease.”"

— Sharecare profile for Dr. Tatiana Thom, MD

"“I was a new patient to Dr Tun, I was extremely satisfied with his service… scheduled an additional labs to target the cause for my visit.”"

— Southcoast Health, Ye Tun MD (Ratings & Reviews)

"“Dr. Thom takes the time to truly listen—never rushing through appointments—and ensures that every concern is addressed thoughtfully.”"

— Healthgrades profile for Dr. Tatiana Thom, MD

Synthesized from public review platforms as of Jul 11, 2026 — sources: [1][2][3][4].

In the News

Nephrology Associates Inc (NAI) Clinical Research Site - Panoramic Health — Jul 15, 2025
Southcoast Health Welcomes New Providers in Cardiology, Internal Medicine, Nephrology & Pulmonary Critical Care – New Bedford Guide — Jul 10, 2026
Dr. Winston Y. Shih, MD - Danbury, CT - Nephrology - Request Appointment — Dec 29, 2025

Information sourced from the clinic's website as of July 11, 2026. Own this clinic? Claim or correct this listing.