▁the ▁w rist . ▁ ▁The ▁He af ▁test ▁was ▁dis cont in ued ▁in ▁ 2 0 0 5 ▁because ▁the ▁manufact urer ▁de emed ▁its ▁production ▁to ▁be ▁finan cially ▁uns ust ain able ▁after ▁manufact ur ers ▁could ▁not ▁be ▁found ▁for ▁t uber cul in ▁or ▁He af ▁guns . ▁ ▁Until ▁ 2 0 0 5 , ▁the ▁test ▁was ▁used ▁in ▁the ▁United ▁Kingdom ▁to ▁determine ▁if ▁the ▁B CG ▁v acc ine ▁was ▁needed ; ▁the ▁Mant oux ▁test ▁is ▁now ▁used ▁instead . ▁ ▁The ▁He af ▁test ▁was ▁preferred ▁in ▁the ▁UK , ▁because ▁it ▁was ▁thought ▁to ▁be ▁easier ▁to ▁interpret , ▁with ▁less ▁vari ability ▁between ▁obser vers , ▁and ▁less ▁training ▁was ▁required ▁to ▁admin ister ▁and ▁read ▁the ▁test . ▁ ▁Pat ients ▁who ▁exhib ited ▁a ▁negative ▁reaction ▁to ▁the ▁test ▁were ▁considered ▁for ▁B CG ▁v acc ination . ▁ ▁The ▁He af ▁test ▁was ▁used ▁to ▁test ▁for ▁t uber cul osis ▁in ▁ad oles c ents ▁aged ▁around ▁ 1 3 – 1 4 . ▁__ TO C __ ▁ ▁Pro cedure ▁A ▁He af ▁gun ▁was ▁used ▁to ▁inject ▁multiple ▁samples ▁of ▁testing ▁ser um ▁under ▁the ▁skin ▁at ▁once . ▁The ▁need le ▁points ▁were ▁di pped ▁in ▁t uber cul in ▁pur ified ▁protein ▁derivative ▁( PP D ) ▁and ▁pr icked ▁into ▁the ▁skin . ▁A ▁He af ▁gun ▁with ▁dispos able ▁single - use ▁heads ▁was ▁recommended . ▁ ▁The ▁gun