Background: LTA,developed by Born,remains the “gold standard” diagnostic test for platelet function disorders,however, this method has limitations to application because it does not allow reliable assessment of patients with thrombocytopenia-the number of cells under study in a sample should be at least fifty thousand. Consequently, platelet functional activity needs to be assessed in patients with unspecified thrombocytopenia and hemorrhagic events.

Aims: Studying the possibility of using the light transmission fluctuation method (LTF) to assess the platelet functional activity in patients with thrombocytopenia.

Methods: The study included 15 children with thrombocytopenia referred for bleeding assessments.In order to prepare samples of PRP plasma,the blood from patients was centrifuged at 1000 rpm for 10 minutes,followed by measuring the number of platelets in the test sample. Plasma of 10 healthy volunteers was studied as a control group. The density of 20,000 platelets/μL in the test samples was achieved by mixing PRP with PPP plasma which were centrifuged in three stages. LTA was studied using an ALAT-2 laser aggregation analyzer with 4 inducers:ADP, adrenaline, ristocytin, collagen.

Results: Plasma samples from healthy volunteers showed little or no response according to the Born method. According to the light transmission fluctuation method(LTF),the formation of aggregates for ADP was from 1.1 to 4.3c.u.(average value 2.93c.u.), adrenaline-from 1 to 6.2c.u. (3.69c.u.), ristomycin-from 1.2 to 9.4c.u.(4.6c.u.), collagen-from 5.5 to 17.1c.u. (10.5c.u.). The number of platelets in the studied samples varied from 0 to 50cells/l (23.6cells/l). Patients showed a more pronounced response to inducers-13 of 15 patients had a response to ristocytin and collagen according to the Born method. Three patients had a response to ADP according to the Born method. There was no adrenaline based on the Born method. According to the LTF method,the response to the addition of the inducer was similar to normal.

Conclusions: Patients with thrombocytopenia have platelet reactivity compared to healthy volunteers. The LTF method makes it possible to assess the aggregation ability with a significant platelet decrease, however,additional tests are required for a more detailed study.

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/the-analysis-of-platelet-functional-activity-in-patients-with-thrombocytopenia/