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Our Practice

For 18 years, Arkana has delivered exceptional patient care, research and education with one thought in mind: the more we all learn, the more we can do.

Our 17 fellowship-trained pathologists have decades of experience interpreting biopsies.

Arkana is committed to providing doctors with the highest quality, clinicopathologic discussion possible. We recognize that in order to best serve the needs of our clinicians we must work together with them, not just as a lab, but as an extension of their practice. It is our goal to help equip doctors with the results they need to deliver the most effective patient care possible. As pathologists, we recognize that the longest period in a patient’s life is the timeframe between the day he/she has a biopsy, and the day the result arrives.

When we opened our doors in 2001, we already had a top-notch physician and researcher in Arkana’s founder, Dr. Patrick Walker. Dr. Walker began reading renal biopsies in 1978. For the next 23 years, he worked in university settings where he read biopsies, did research, and taught. Following his desire to focus exclusively on kidney disease, he opened Nephropath and surrounded himself with physicians and staff who shared his vision.

Research, education, and innovation are hardwired into Arkana’s culture. But what makes our practice indispensable to nephrologists around the US is the high level of interaction with the pathologists who read the biopsies. Today, just as we did on day one, the pathologist that reads your case is the pathologist that calls you to discuss the results.

Over the last few years, our curiosity, innovations, and growing team of doctors — the finest and most concentrated in the field anywhere in the world — have all contributed to a constantly expanding practice. Today we provide renal pathology, serology, neuropathology, biopharma services, and molecular (genomic) services. We’ve doubled down on our commitment to research and teaching. We are actively working toward the day that our research yields breakthroughs that make our services unnecessary. Eradicating rare and common diseases is the end game of all of our efforts because patient health is foremost in our minds every day.


Patrick Walker opens kidney pathology lab as Nephropathology Associates


Began calling ourselves Nephropath and initiated a same-day renal biopsy service


Nephropath begins genetic research


Changes its name to Arkana

Our Doctors

Clint Abner View Profile
Clint Abner, Ph.D.
Contract Research Development Manager
Josephine Ambruzs View Profile
Josephine Ambruzs, M.D., M.P.H.
Jane M. Bell View Profile
Jane M. Bell, M.D.
Alejandro Best View Profile
Alejandro Best, M.D.
Christie Boils View Profile
Christie Boils, M.D.
T. David Bourne View Profile
T. David Bourne, M.D.
Neuropathologist, Nephropathologist
Clarissa Cassol View Profile
Clarissa Cassol, M.D.
Tiffany Caza View Profile
Tiffany Caza, Ph.D., M.D.
Shana Coley View Profile
Shana Coley, M.D., Ph.D.
Director of Transplant Translational Research & Multiplex Imaging Center
L. Nicholas Cossey View Profile
L. Nicholas Cossey, M.D.
Physician Director, Nephropathologist
Zeljko Dvanajscak View Profile
Zeljko Dvanajscak, M.D., M.S.
Gabriel Giannini View Profile
Gabriel Giannini, M.D.
Samar Hassen View Profile
Samar Hassen, Ph.D.
Research Scientist
Randy Haun View Profile
Randy Haun, Ph.D.
Senior Scientist
Danni Holanda View Profile
Danni Holanda, M.D.
Daniel Kenan View Profile
Daniel Kenan, Ph.D., M.D.
Research Scientist
Michael Kuperman View Profile
Michael Kuperman, M.D.
Rebecca May View Profile
Rebecca May, M.D., Ph.D.
Renal Pathologist
Chris Larsen View Profile
Chris Larsen, M.D.
Executive Director, Nephropathologist
Joel Murphy View Profile
Joel Murphy, M.D.
Shree G. Sharma View Profile
Shree G. Sharma, M.D.
Laboratory Director, Nephropathologist
Patrick D. Walker View Profile
Patrick D. Walker, M.D.
Founder, Nephropathologist
Jon D. Wilson View Profile
Jon D. Wilson, M.D.
Neuropathologist, Molecular Pathologist
Stephen Bonsib View Profile
Stephen Bonsib, M.S., M.D.
Emeritus Nephropathologist
Fred Silva View Profile
Fred Silva, M.D.
Emeritus Nephropathologist