A trainer receives notice that a horse has tested positive for a prohibited substance. The laboratory result appears conclusive. Then, while reviewing the records, something seems wrong. A custody form is incomplete. A sample remained in storage overnight with no recorded time of transfer. Two witnesses disagree about who handled the evidence. The paperwork does not clearly establish how the sample moved from the horse to the laboratory.

For someone familiar with criminal trials, the natural question may be whether the evidence can be thrown out. However, the answer under the Horseracing Integrity and Safety Authority’s (HISA) Anti-Doping and Medication Control Program is more complicated. Chain of custody serves the same basic purpose in almost every legal setting in that it provides confidence that the evidence eventually tested or presented is the same evidence originally collected and that its integrity was preserved along the way.