Thomas William O'Brien

Thomas William “OB” O’Brien, 63, tragically passed away in Fairfax, VA on November 29, 2025. Tom was born in Manhattan, NY on January 5, 1962, to James and Jeanne Dosso O’Brien, the youngest of 3 children. He grew up in Yonkers and attended Mount St. Michael Academy in the Bronx where he played football.

After high school he earned his undergraduate degree in Bio-Chemistry at The Catholic University. He later earned a Master’s and PhD in Chemistry at American University in Washington, DC. Married in 1997 to Jackie, they raised 4 children together.

While deployed to Kuwait in support of the Biological Defense Research Program, as a civilian in the Navy, Tom along with Bill Nelson firmed up the idea to start a company. In 1998, after spirited discussions, Tom and Bill felt they needed their colleagues Dr. Gary Long and the late Dr. Beverly Mangold to join them in starting Tetracore, a biotechnology company providing detection tools for clinical, animal health, and biothreat testing. Tetracore now employs almost 100 people and has expanded to include CirrusDX laboratory.

Tom loved all sports, but especially the New York Jets and Yankees. In recent years he enjoyed attending Caps hockey games. He coached Braddock Road Youth Football for many years as well as CYO basketball. He was a visible presence as a volunteer at St. Ambrose Catholic Church when his children attended school there. He supported science programs there as well as at St. Paul VI High School.

His cabin in West Virginia was his happy place. He enjoyed spending as much time there as possible. He loved fishing and enjoyed the peace and quiet as he watched wildlife from the screened in porch. He also enjoyed walking the loop and catching up with the neighbors.

Known by many names, Tom, Tommy, OB, Coach, he was a great friend and coach to many and will not be forgotten. His friends were dear to him, and he made an effort to stay in touch with his many friends from elementary, high school and college as well as friends from work, coaching and his other interests.

Tom was predeceased in death by his son Justin Stone, his sister Jeanne Cappello, and parents, James and Jeanne O’Brien. He is survived by his wife Jackie of 28 years, sons Kameron Stone and Patrick O’Brien, daughter Molly O’Brien and his brother Jim O’Brien along with his nieces and nephews, cousins and many other family members and friends.

We wish to thank the Mlezva family, the Burk family, Oak View Elementary School and Community, Burke Community Church, St. Ambrose Catholic Church, friends and family and the many others who have shown such support to our family during this difficult time. We are overwhelmed with gratitude and words cannot express our appreciation for your generous gifts, love and prayers.

Visitation will be on Thursday, December 18 from 5-7pm.

Funeral mass is on Friday, December 19, at 11:00 am at St. Ambrose Catholic Church in Annandale, VA.

In lieu of flowers, memorial contributions may be sent to Mount St. Michael Academy: https://www.mtstmichael.org/giving/, or your local fire department.