RESULTS	Responses appeared to be less variable when expressed as percentage change in the ratio of blood flow ( infused : noninfused ) in both arms than as percentage change in blood flow in the infused arm alone , as indicated by repeatability coefficients ( 15 % vs 21 % , 2.5 pmol min-1 and 11 % vs 13 % , 10 pmol min-1 ; ratio vs infused arm alone ) .\