▁the ▁cu v ette , ▁the ▁test ▁is ▁inc ub ated ▁for ▁three ▁minutes ▁before ▁the ▁chosen ▁ag on ist ▁is ▁added . ▁The ▁test ▁is ▁then ▁started , ▁and ▁plate let ▁aggreg ation ▁is ▁recorded ▁at ▁approximately ▁ 0 . 5 ▁second ▁intervals ▁for ▁six ▁minutes . ▁Three ▁parameters ▁are ▁calculated : ▁aggreg ation , ▁velocity ▁and ▁area ▁under ▁the ▁curve ▁( A UC ). ▁A ggreg ation ▁( in ▁A U ) ▁is ▁the ▁maximum ▁height ▁of ▁the ▁aggreg ation ▁curve , ▁and ▁velocity ▁( in ▁A U / min ) ▁is ▁the ▁maximum ▁slope ▁of ▁the ▁curve . ▁A UC ▁is ▁the ▁most ▁important ▁parameter . ▁It ▁is ▁recorded ▁in ▁Units ▁( U ), ▁and ▁is ▁affected ▁by ▁both ▁the ▁height ▁and ▁the ▁slope ▁of ▁the ▁aggreg ation ▁curve , ▁and ▁is ▁the ▁best ▁overall ▁measure ▁of ▁plate let ▁activity . ▁ ▁Multi plate ▁Test s / Re ag ents ▁ ▁AD P test ▁A den os ine ▁di ph osph ate ▁( AD P ) ▁is ▁a ▁plate let ▁ag on ist . ▁When ▁it ▁is ▁added ▁to ▁sal ine - d il uted ▁whole ▁blood ▁in ▁the ▁test ▁cu v ette , ▁it ▁stim ul ates ▁the ▁AD P ▁re cept ors ▁on ▁plate lets , ▁activ ating ▁the ▁plate lets . ▁The ▁activation ▁of ▁the ▁plate lets ▁leads ▁to ▁shape ▁change ▁and ▁de gr an ulation , ▁and ▁the ▁released ▁content ▁of ▁the ▁gran ules ▁further ▁activ ates ▁the ▁plate lets . ▁Activ ation ▁also ▁indu ces