Fig. 2From: Effects of repeated comparative intradermal tuberculin testing on test results: a longitudinal study in TB-free red deerIndividual seasonal (winter 2012 to winter 2015) skin test response in mm of 18 red deer hinds to the intradermal injection of a avian purified protein derivative (aPPD) and b bovine PPD (bPPD). Dashed lines indicated for cut-off valueBack to article page