Grant Nybakken, M.D.
Grant Nybakken, M.D.
Grant E. Nybakken, M.D. earned his degree in Biology with High Honors from Haverford College before completing an M.D./Ph.D. in Biophysics at Washington University School of Medicine, where his research focused on the structural mechanisms of West Nile virus neutralization. Following his medical training, he completed residencies and fellowships in pathology, hematopathology, and surgical pathology at institutions including the University of Pennsylvania and Stanford.
Dr. Nybakken’s extensive research contributions in hematopathology and molecular diagnostics have been widely published in peer-reviewed journals. Board-certified in Anatomic and Clinical Pathology as well as Hematopathology, Dr. Nybakken is recognized for his expertise in laboratory medicine, medical technology, and quality assurance in clinical pathology.
Medical Degree:
Washington University School of Medicine
Residency:
University of Pennsylvania – Philadelphia
Fellowship:
Hematopathology, Stanford Hospital and Clinics
Surgical Pathology, Stanford Hospital and Clinics
Board Certification:
Anatomic and Clinical Pathology, Hematology-Pathology
Ruth Zhang, M.D.
Ruth Zhang, M.D.
Dr. Ruth Zhang, MD is a pathologist based in San Francisco, California, with a specialization in gastrointestinal and hepatobiliary pathology. She completed her B.S. in Biology at Duke University and earned her M.D. from the Keck School of Medicine at the University of Southern California. Dr. Zhang underwent residency and fellowship training at the University of California, San Francisco, where she also served as Chief Resident in the Department of Pathology.
Her research focuses on pathology and laboratory medicine, with numerous peer-reviewed publications exploring topics like gastrointestinal cancer and immunomodulation in osteogenesis. Dr. Zhang has received multiple awards, including the Nancy E. Warner, MD Award, and has presented her work at national conferences. She holds medical licensure in California and is an active member of several professional societies, including the American Society for Clinical Pathology and the United States and Canadian Academy of Pathology.
Medical Degree:
USC Keck School of Medicine, Los Angeles, CA
Residency:
University of California – San Francisco
Fellowship:
Surgical, Gastrointestinal, and Hepatobiliary Pathology – UCSF
Natalie Patel, M.D.
Natalie Patel, M.D.
Dr. Natalie Patel, MD is a board-certified anatomic and clinical pathologist with an active California medical license. She served as an attending physician, Director of Microbiology, and Treasurer at El Camino Medical Group Inc., based at El Camino Health in Mountain View, CA.
Dr. Patel earned her doctorate from Saint George’s University, graduating Magna Cum Laude, and holds a Bachelor of Science in Biomedical Engineering from the New Jersey Institute of Technology. She completed her residency in anatomic and clinical pathology at Yale-New Haven Hospital, where she was elected Chief Resident, followed by fellowships in surgical and gastrointestinal/liver pathology.
With extensive experience in pathology, Dr. Patel has authored multiple peer-reviewed publications and book chapters. She actively participates in professional associations such as the College of American Pathologists and the American Society for Clinical Pathology. She is also involved in community service and holds fluency in English and conversational skills in Gujarati.
Medical Degree:
Saint George’s University
Residency:
Chief Resident, Yale-New Haven Hospital
Fellowship:
Gastrointestinal/Liver Pathology, Yale-New Haven Hospital
Surgical Pathology, UC San Diego
Board Certification:
California State Board of Medicine
Anatomic and Clinical Pathology Board
William Rogers, M.D.
William Rogers, M.D.
Will received his BS from Stanford University, followed by his MD from The University of Southern California Keck School of Medicine. He then completed his Anatomic and Clinical Pathology residency at Stanford University. Also at Stanford he completed two subspecialty fellowships: one in Gynecologic and Breast Pathology and one in Cytopathology. He is board certified in Anatomic and Clinical Pathology and Cytopathology.
Will serves as the Enterprise Medical Director of Pathology and Clinical Laboratory at El Camino Health (Mountain View and Los Gatos campuses). He is the medical director of Blood Bank/Transfusion service and is Co-Chair of the El Camino Hospital Transfusion Safety Committee.
Will is joined in life by 1 amazing wife, 2 fantastic boys, 1 dog, 4 cats, 3 tortoises, a boat, and about 20 fishing rods (not that he really knows how to fish well).
Medical Degree:
USC Keck School of Medicine, Los Angeles, CA
Residency:
Stanford University
Fellowship:
Surgical, GYN, and Breast Pathology, Cytopathology – Stanford University
Board Certification:
Anatomic and Clinical Pathology, Cytopathology
Special Interests:
Gynecologic Pathology, Cytopathology, General surgical pathology, Breast Pathology
Sebastian Sasu, M.D.
Sebastian Sasu, M.D.
Medical Degree:
Iuliu Hatieganu University of Medicine and Pharmacy, Cluj, Romania
Residency:
University of Southern California, LAC-USC Medical Center, Los Angeles
Fellowship:
Hematopathology, University of California- Los Angeles
Board Certification:
Anatomic and Clinical Pathology, Hematopathology
Special Interests:
Hematopathology including flow cytometry, FISH and molecular diagnostics, Surgical Oncologic Pathology with a focus on Breast, Gynecologic and Gastro-Intestinal Pathology
Sarah Calkins, M.D.
Sarah Calkins, M.D.
Prior to joining Peninsula Pathologists, Sarah was an Associate Professor of Pathology at the University of California San Francisco. As part of the Cytopathology division, she staffed the pathologist-performed Fine Needle Aspiration Biopsy Clinic, where she used her expertise to perform palpation and ultrasound-guided FNAs with a focus on maximizing the diagnostic potential of small samples. She also has a subspecialty focus in head and neck pathology with interests in salivary gland tumors and HPV-related diseases. One of her many roles as an educator included serving Anatomic and Clinical Pathology Residency Program Director from 2017 until joining PPMG in 2023. She looks forward to bringing her clinical and leadership skills to this exciting pathology practice.
Sarah earned her MD from the University of Toledo where she also participated in the Post-Sophomore Pathology Fellowship Program and received the American Society for Clinical Pathology Award for Excellence and Achievement. She then completed Anatomic and Clinical Pathology Residency, Surgical Pathology Fellowship, and Cytopathology Fellowship at UCSF. While training, she was awarded the Anatomic Pathology Fellow Teaching Award.
Sarah lives in San Francisco. She enjoys hiking, live music, wine country, trying new restaurants, park days, and anything with her two dogs.
Medical Degree:
University of Toledo College of Medicine
Residency:
Anatomic and Clinical Pathology – University of California San Francisco
Fellowship:
Surgical Pathology – University of California San Francisco
Board Certification:
Anatomic and Clinical Pathology, Cytopathology
Special Interests:
Cytopathology, Small Biopsies, Head and Neck Pathology, Thyroid Pathology, Small Samples for Advanced Molecular Testing
Jenny Kuo, M.D.
Jenny Kuo, M.D.
Dr. Jenny Kuo is a skilled pathologist at Peninsula Pathologists in the San Francisco Bay Area. With a medical degree and residency training in pathology, she provides accurate diagnostic services for various medical conditions. She is dedicated to staying current with the latest advancements in her field and is a trusted member of the medical community. In her free time, she enjoys hiking and exploring California’s natural landscapes.
Medical Degree:
University of Southern California-School of Medicine
Residency:
University of Southern California-School of Medicine
Fellowship:
Surgical Pathology-University of Southern California-School of Medicine
Fellowship:
Transfusion Medicine-Stanford Hospital and Blood Center
Board Certification:
Anatomic and Clinical Pathology, Transfusion Medicine
Special Interests:
Anatomic and Clinical Pathology
Thuy Nguyen, M.D.
Thuy Nguyen, M.D.
Dr. Thuy Nguyen is a board-certified anatomic and clinical pathologist with fellowship training in gastrointestinal and hepatobiliary pathology. She serves as Medical Director for Laboratory and Pathology and Transfusion Committee Chair at Sutter Health’s Mills-Peninsula Medical Center (MPMC). She is also a managing partner and board member for Peninsula Pathologists Medical Group (PPMG) Inc. She holds active medical staff appointments at Sutter Health’s MPMC, Palo Alto Medical Foundation, San Mateo County Hospital and Clinics and Dignity Health’s Sequoia Hospital.
Thuy received her Medical Doctorate (M.D.) from the University of Minnesota. She then completed anatomic and clinical pathology residency and surgical pathology fellowship at the University of California San Francisco (UCSF). She also completed fellowship training in gastrointestinal and hepatobiliary pathology fellowship program under Dr. Linda Ferrell.
Thuy resides in San Francisco with her family (husband, 1 child and 1 dog). She and her family enjoy live music, park days, museums, and zoos. She and her husband are gastronomes always on the look-out for great restaurants and new recipes to try. Thuy is also a proficient baker that dabbles in cake decorating in her free time.
Medical Degree:
University of Minnesota Medical School
Residency:
University of California-San Francisco
Fellowship:
Surgical Pathology – University of California-San Francisco
Fellowship:
Gastrointestinal and Hepatobiliary Pathology – University of California-San Francisco
Board Certification:
Anatomic and Clinical Pathology
Special Interests:
Gastrointestinal, Liver, Anatomic and Clinical Pathology
Sourav Ray, M.D.

Sourav Ray, M.D.
Sourav is a Board-Certified Anatomic and Clinical Pathologist with dual board certification in Dermatopathology. He is currently Chair of Pathology at the MPMC Division of Sutter Health and recent liaison to the Sutter system-wide Integrated Network Cancer Program. He is a strong believer in integrated multidisciplinary cancer treatment with focus on locally led tumor boards.
Prior to joining PPMG Sourav was a resident and fellow at the University of Pittsburgh Medical Center during a golden era when he was fortunate enough to learn directly from many of the world’s foremost pathologists.
Sourav resides in San Francisco with his partner, 3 kids, and 2 rescue dogs. He has a special interest in beer, tennis, and the intersection of Eastern and Western classical music (not necessarily in that order). He currently serves on the Board of Directors of Peninsula Pathologists Medical Group.
Medical Degree:
Albany Medical College
Residency:
University of Pittsburgh-School of Medicine
Fellowship:
Dermatopathology-University of Pittsburgh-School of Medicine
Board Certification:
Anatomic Pathology, Clinical Pathology, and Dermatopathology
Special Interests:
Cutaneous diseases, soft tissue tumors, lymphomas
Judy A. Alonzo, M.D.

Judy A. Alonzo, M.D.
Dr. Judy Alonzo is a board-certified anatomic and clinical pathologist with broad range experience in general Anatomic Pathology and Laboratory Medicine with interests in urologic and gastrointestinal pathology. During her time with Peninsula Pathologists Medical Group (PPMG) she served as group President for fourteen years, during which time the group’s broad array of subspecialty expertise was nurtured and its independent anatomic pathology laboratory was established. At Peninsula Hospital, she was a member of Peninsula Hospital infection control, patient safely and medical executive committees and served as Pathology Department Chair for four years. She served as the CLIA Medical Director for PPMG’s independent anatomic pathology laboratory for fourteen years and Sutter Health Shared Laboratory for six years. She holds active staff privileges at Mills-Peninsula Health Services, Palo Alto Medical Foundation, Sequoia Hospital and San Mateo Medical Center.
Prior to joining Peninsula Pathologists Medical Group, Dr. Alonzo earned her medical degree at the University of Colorado Health Sciences Center. She completed her Anatomic Pathology and Laboratory Medicine residency and Surgical Pathology Fellowship at the University of California – San Francisco, where she also served as Chief Resident. Following completion of her training, she was offered and accepted an appointment as Assistant Clinical Professor in the Department of Laboratory Medicine at the University of California – San Francisco and worked at the San Francisco Veterans Affair Medical Center in the Departments of Laboratory Medicine and Anatomic Pathology where she enjoyed taking care of the pathology needs of our veterans and teaching and supervising residents.
Medical Degree:
University of Colorado School of Medicine
Residency:
University of California-San Francisco
Fellowship:
Surgical Pathology-University of California-San Francisco
Board Certification:
Anatomic and Clinical Pathology
Special Interests:
Gastrointestinal, Liver and Prostate Pathology






