An experiment designed to assess the components of variability of a number of measures
of platelet aggregability showed that the ADP ED50 (the estimated dose of adenosine
diphosphate at which primary aggregation occurs at half its maximum velocity) had
the least method error of any of the parameters measured, but that none had a very
high between-person component of variability. A simultaneous comparison of a syringe
technique and a free-flowing technique for venepuncture revealed no differential effects
on the aggregation parameters measured. An enforced increase in the stirring speed
in the aggregometer led to an experiment which showed that such a change did not apparently
affect the ED50s.
Keywords
Platelet aggregation - Dose response - Variability - Stirring speed
