The automation of routine light transmission platelet aggregation.
BACKGROUND
The investigation of platelet function by aggregometry requires specialist equipment and is labour intensive. We have developed an automated platelet aggregation method on a routine coagulation analyser.


METHODS
We used a CS-2000i (Sysmex) with prototype software to perform aggregation in platelet-rich plasma (PRP), using the following agonists: ADP (0.5-10 μm), epinephrine (0.5-10 μm), collagen (0.5-10 mg/μL), ristocetin (0.75-1.25 mg/mL) and arachidonic acid (0.12-1.0 mm). Platelet agonists were from Hyphen Biomed, and an AggRAM aggregometer (Helena Biosciences) was used as the reference instrument.


RESULTS
CS-2000i reaction cuvette stirrer speed was found to influence reaction sensitivity and was optimized to 800 rpm. There were no clinically significant changes in aggregation response when the PRP platelet count was 150-480 x 10(9) /L, but below this there were changes in the maximum amplitude (MA) and slope (rate). Dose response with each of the agonists was comparable between CS-2000i and an AggRAM aggregometer and normal subjects receiving antiplatelet drugs. Aggregation imprecision was similar on both the CS-2000i and AggRAM systems, with a cv for 2-5 μm ADP MA and slope varying between 3-12%.


CONCLUSIONS
Our preliminary studies indicated that optimal sensitivity using the CS-2000i was obtained with a reaction cuvette stirrer speed of 800 rpm and a PRP platelet count of 200-300 x 10(9) /L; aggregation with a PRP count <100 x 10(9) /L showed poor sensitivity. Imprecision and detection of antiplatelet drug effects was similar between the CS-2000i and AggRAM. These data demonstrate that CS-2000i is comparable to a stand-alone aggregometer, although CS-2000i has the advantages of walk-away technology and also required a smaller sample volume than the AggRAM (44% less).
Haemostasis Research Unit, Department of Haematology, University College London, London, UK.
A S
AS
Lawrie
K
K
Kobayashi
P J
PJ
Lane
I J
IJ
Mackie
S J
SJ
Machin
D000244:Adenosine Diphosphate / Q000494:pharmacology; D057205:Automation, Laboratory / Q000295:instrumentation / Q000592:standards*; D001792:Blood Platelets / Q000187:drug effects*; D002478:Cells, Cultured; D003094:Collagen / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects*; D010979:Platelet Function Tests; D012310:Ristocetin / Q000494:pharmacology; D012680:Sensitivity and Specificity
D012310:Ristocetin; D000244:Adenosine Diphosphate; D003094:Collagen; D004837:Epinephrine
Automation; platelet aggregation