Use of native or platelet count adjusted platelet rich plasma for platelet aggregation measurements

Abstract

Background: It is still not clear whether native or platelet count adjusted platelet rich plasma (PRP) should be used for platelet aggregation measurements. Aim: To evaluate the necessity of using adjusted PRP in platelet function testing. Methods: Platelet aggregation with native PRP and adjusted PRP (platelet count: 250/nl, obtained by diluting native PRP with platelet poor plasma) was performed on the Behring Coagulation Timer (BCTH) using ADP, collagen, and arachidonic acid as agonists. Healthy subjects, patients on antiplatelet treatment, and patients with thrombocytosis (platelet counts in PRP . 1250/nl) were investigated. Results: No significant differences in the maximum aggregation response were seen when using either native or adjusted PRP from healthy subjects and patients on antiplatelet treatment. Nevertheless, some patients taking aspirin or clopidogrel showed reduced inhibition of ADP and arachidonic acid induced aggregation in adjusted PRP but not in native PRP. The maximum velocity of healthy subjects and patients on antiplatelet treatment varied significantly as a result of the degree of dilution of the adjusted PRP. Surprisingly, the BCT provided good results when measuring platelet aggregation of native PRP from patients with thrombocytosis, whereas commonly used aggregometers could not analyse platelet aggregation of native PRP in these patients. Conclusion:The time consuming process of PRP adjustment may not be necessary for platelet aggregation measurements. Moreover, using adjusted PRP for monitoring aspirin or clopidogrel treatment may falsify results. Therefore, it may be better to use native PRP for platelet aggregation measurements, even in patients with thrombocytosis.

Recommendations for the standardization of light transmission aggregometry: a consensus of the working party from the platelet physiology subcommittee of SSC/ISTH

“…Recent studies demonstrated that platelet counts in PRP within the range that is observed in PRP samples from subjects with normal platelet count in whole blood do not affect the results of LTA studies [19][20][21][22]. Therefore, the common practice of adjusting the platelet count in PRP with autologous PPP is not recommended, because it is unnecessary and may impair the platelet responsiveness to agonists [21].…”

“…After review of the full manuscripts by the panel members, fifteen further studies were excluded. These 12 manuscripts, coupled with two extra studies identified by manual review and by consultation among members of the working group, resulted in a total of only 14 relevant studies [17][18][19][20][21][22][23][24][25][26][27][28][29][30] that were used to help refine the RAND survey and write the present recommendations ( Fig. 1).…”

Platelet aggregation studies: autologous platelet-poor plasma inhibits platelet aggregation when added to platelet-rich plasma to normalize platelet count

“…However, this practice could also affect platelet function independently of the induced change in platelet count, as PPP may contain substances affecting platelet function that are released by platelets or other blood cells during high-speed centrifugation of blood samples necessary to obtain PPP. 5 This study examines whether or not dilution of PRP with autologous PPP also affects the results of platelet aggregation studies independently of the induced decrease in platelet count.…”

Guilty by Association: Platelet Reactivity and Inflammation in Psoriatic Arthritis

“…The platelet count is not reported, and by implication the results were not corrected for the possible influence of the well described reactive thrombocytosis that is associated with disease activity in PsA, although previous work has shown that platelet count does not significantly influence platelet aggregation measurements 10 . Also, the platelet function assays that were used assessed the platelet responses, separately, to each of only 2 concentrations of arachidonic acid and a single concentration of ADP, the concentrations tested were in the low submaximal range, and the clinical applicability of such an approach has been called into question 11 .…”