Associations of obex scores with antemortem testing and the genetic background of farmed elk. As obex scores increased, a greater proportion of positive 132MM animals was observed, along with a higher sensitivity observed through both nasal brush and RAMALT biopsy specimen analyses. NB, nasal brush analysis by RT-QuIC; RB, RAMALT biopsy specimen analysis by RT-QuIC; GT, 132MM allele proportion among animals identified as CWD positive.