Table 2.

Streamlined panel of agonists with interpretative notes for diagnosing platelet function defects

Agonist	Concentration	% of maximal aggregation, mean ± SD	Expected	Abnormal pattern and further testing
ADP*	10μM	59.8% ± 12.5%	Maximal, sustained aggregation and secretion	Reduced or transient aggregation and absent secretion: use 30μM
Adrenaline*	10μM	70.3% ± 13.7%	Biphasic aggregation with secretion coincident with second phase	Reduced or absent primary wave and absent secretion: use 30μM
Arachidonic acid	1mM	71.0% ± 8.5%	Maximal, sustained aggregation and secretion	Absent or delayed/reduced aggregation and secretion: use U46619 (3μM)
PAR-1 receptor–specific peptide (SFLLRN)	100μM	73.8% ± 11.1%	Maximal, sustained aggregation and marked secretion	Transient aggregation and reduced secretion: use PAR-4 receptor–specific peptide (AYPGKF; 500μM).
Collagen*	1 μg/mL	50.4% ± 22.5%	Sustained aggregation and secretion	Reversible aggregation and absent secretion: use 3 μg/mL and collagen-related peptide (CRP; 3 μg/mL) or convulxin
Ristocetin	1.5 mg/mL	70.8% ± 16.1%	Maximal sustained aggregation (often biphasic) and secretion	Reduced or absent aggregation and secretion

Different concentrations of agonists with the percentage of maximal aggregation ± SD are shown.

^*ATP secretion from dense granules should be measured for the following agonist concentrations: ADP (30μM), adrenaline (30μM), arachidonic acid (1mM), PAR-1–specific peptide (100μM), and collagen (3 μg/mL).