Platelet aggregation test has been widely used to detect congenital and acquired abnomalities of platelet functions. However, it is difficult to measure platelet aggregation in patients with thrombocytopenia, such as idiopathic thrombocytopenic purpura, acute leukemia, aplastic anemia, SLE, and liver cirrhosis.
We demonstrated the effect of low platelet number in platelet rich plasma (PRP) on platelet aggregation using new model of aggregometer, Dual Sample Aggregometer Model DP-247-E (SIENCO) and recorder, Unicorder U-225-MS39 (NIHON DENSHI KOHGAKU).
Blood samples were taken from eight healthy volunteers without ingestion of any drugs known to affect platelet aggregation at least ten days prior to study.
PRP was diluted with autologous platelet poor plasma (PPP) to make various consentrations of PRP as follow; 30×104/mm3, 15×104/mm3, 10×104/mm3, 7.5×104/mm3, 5.0×104/mm3, 3.0×104/mm3. As aggregating reagents, was used ADP (final concentration: 1×10-5M, Siguma), Epinephrine (1×10-4M, DAIICHIKAGAKU), and Collagen (25μg/ml, Sigma). We measured the maximum percentage of aggregation and the pattern of aggregation curve.
With ADP, no significant change was seen at or above 5.0×104/mm3 of platelet consentration in PRP. However, aggregation was significantly diminished at 3.0×104/mm3. When epinephrine and collagen were used, aggregation remained normal at or above 7.5×104/mm3 of platelet concentration.
It was concluded that platelet aggregation was measurable with this aggregometer when the platelet concentration was more than 5.0×104/mm3. 7.5×104/mm3, 7.5×104/mm3 with ADP, epinephrine and Collagen respectively.