Dedicated to Kidney Health
Across the North Bay
Founded in 2015, Associated Kidney Specialists of the North Bay has grown from a single-physician practice into a trusted multi-county nephrology group — serving thousands of patients with expertise, compassion, and genuine community commitment.
A Decade of Excellence
in Nephrology
When Dr. Nagarathna Manjappa established Associated Kidney Specialists of the North Bay in 2015, her mission was straightforward but ambitious: bring world-class nephrology expertise to the communities of Northern California's North Bay — and deliver it with the personal, compassionate touch that patients deserve.
Starting in Napa, the practice quickly gained the trust of patients, families, and referring physicians throughout the region. As word spread about AKSNB's quality of care and the warmth of its team, demand grew rapidly. The practice expanded its reach to Solano County, then Sonoma, and eventually Lake County — establishing AKSNB as a regional leader in nephrology care across Northern California.
Today, AKSNB is home to three board-certified nephrologists who collectively bring decades of training and experience — spanning Stanford, Tufts, Brown, Boston Medical Center, and SUNY Brooklyn — to the region. Together, they provide comprehensive kidney services covering the full spectrum of nephrology: from chronic kidney disease management and hypertension to dialysis, kidney transplant evaluation, critical care nephrology, and complex glomerular diseases. Our physicians collaborate closely with primary care providers, hospitalists, and transplant centers to ensure seamlessly coordinated, evidence-based care at every stage of each patient's kidney health journey.
Explore Our Services
Est. 2015
Napa, CA
Our Journey
A decade of growth, learning, and expanding care across the North Bay.
2015
Napa Nephrology Associates was founded by Dr. Manjappa with a mission to bring specialized nephrology care to underserved Northern California communities. From the outset, the practice established coverage across both Napa and Lake Counties, addressing a critical gap in regional kidney care.
2017
In response to growing patient demand, the practice welcomed a second full-time nephrologist, strengthening the team's capacity to deliver comprehensive, continuity-based nephrology care across its service areas.
2019
The practice expanded its regional footprint by extending nephrology coverage to Sonoma County, further broadening access to specialized kidney care for patients throughout the North Bay.
2023
Dr. Pei joined the practice, bringing additional expertise and reinforcing the team's commitment to delivering high-quality, patient-centered nephrology services across all locations.
2025
Dr. Lakshman joined the growing practice, and services were extended to the Vallejo community — marking a significant milestone in the practice's continued expansion throughout Northern California.
Meet Our Nephrologists
Three dedicated, board-certified nephrologists united by a shared commitment to exceptional patient care and clinical excellence.
Founder & Medical Director
Nagarathna Manjappa, MD, FASN
Board-Certified Nephrologist
Dr. Nagarathna Manjappa is the founding member of Associated Kidney Specialists of the North Bay. She is a board-certified nephrologist and a Fellow of the American Society of Nephrology (FASN). With her dedicated pursuit of growth and excellence, she has built a practice that has earned unwavering support from the community and recognition for quality of care that can only be found in practices that originate in and grow with the community. She has been recognized as 'Physician of the Year' by Napa Solano Medical Society in 2026.
Dr. Manjappa completed her medical school at Bangalore Medical College, one of the renowned medical schools in India. She completed residency in 2006 and fellowship in nephrology in 2010 at the State University of New York, Brooklyn campus, training under excellent nephrologists. She gained experience working in diverse settings in Kentucky and South Carolina before moving to Napa in 2012.
Areas of Focus
Nephrologist
Trixie Lorraine Cruz Pei, MD
Board-Certified Nephrologist
Dr. Pei joined Associated Kidney Specialists of the North Bay in October 2023. She completed her Internal Medicine residency at Corewell Health Lakeland Hospital in Michigan, and her fellowship in Nephrology at Boston Medical Center, Boston, Massachusetts. She brings a wealth of experience working with diverse communities and a rigorous academic training background. Dr. Pei lives with her family in Napa, with extended family in the area, making her a true member of the community she serves.
Areas of Focus
Nephrologist
Sneha Lakshman, MD
Board-Certified Nephrologist
Dr. Sneha Lakshman joined Associated Kidney Specialists of the North Bay in August 2025. She completed her Internal Medicine Residency at Mass General Brigham (MGB) Salem Hospital, Salem, MA. She completed her Critical Care Fellowship at Brown University — Rhode Island Hospital and The Miriam Hospital, Providence, RI in June 2023. She then continued her training and completed her Nephrology Fellowship at Stanford University — Stanford Health Care, Palo Alto, CA in June 2025. Dr. Lakshman brings cutting-edge expertise from two of the nation's premier medical institutions.
Areas of Focus
Nephrologist
Geetha Narayan, MD
Board-Certified Nephrologist
Dr. Geetha Narayan joined AKSNB in Napa after a stellar 30-year career at prestigious Boston medical institutions. She completed her fellowship at Tufts Medical Center in 1983 and has since served on staff at St. Elizabeth Medical Center, where she held several leadership roles in both clinical and academic arenas, rising to full professorship at Tufts Medical School. She has extensive experience in clinical nephrology, with a scope ranging from common nephrologic diseases to ICU and tertiary care nephrology. With directorship roles in the division of nephrology and medical education, she was actively involved in overseeing residency and nephrology fellowship training programs. She has been the recipient of multiple teaching awards, appeared on the 'Best Doctors' list for consecutive years, and has several publications in peer-reviewed journals. We are pleased she has moved permanently to Napa from Boston.
Areas of Focus
Our Core Values
The principles that guide every aspect of how we care for our patients.
Clinical Excellence
All care is grounded in the latest evidence-based guidelines from the National Kidney Foundation, KDIGO, and the American Society of Nephrology.
Compassionate Care
We treat each patient as an individual — not a diagnosis. Understanding your life circumstances and goals is central to how we practice medicine.
Community Focus
Founded in Napa and expanding across the North Bay, we are deeply invested in the health and wellbeing of the communities we serve.
Continuous Learning
Our physicians actively engage with the nephrology research community to bring the most current advances in kidney medicine to our patients.
Affiliations & Partnerships
AKSNB collaborates with leading healthcare systems and medical organizations to ensure our patients have access to the highest level of coordinated care.
Providence Health Systems
Hospital affiliations and specialist referral network across Northern California.
National Kidney Foundation
Adherence to the latest clinical practice guidelines and patient education resources.
American Society of Nephrology
Active engagement with cutting-edge nephrology research and continuing education.
Ready to Meet Our Team?
We are currently accepting new patients across the North Bay. Contact our office to schedule your first consultation with one of our nephrologists.