B-sample n (General Sporting Terms) a urine or blood sample used in doping tests in professional sports to confirm or invalidate the presence of banned substances in the first sample, the A-sample. See also A-sample Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014