Medina Spirit, the Kentucky Derby winner, heads into the Preakness under a cloud after drug test

The second phase, the split-sample test, comes next in this case and involves a different laboratory. It examines the two remaining samples, which will have spent recent days in a locked freezer and a locked refrigerator. For that, officials solicit the eight capable laboratories in the country, learn which can handle the testing at any given moment, then present a list of options to the trainer, who chooses one. That process, once a laboratory takes on the task, can require two weeks to a month and sometimes longer, Scollay said.