Can platelet aggregometry be standardized?

Abstract

Platelet aggregometry is an important technique which is frequently used by hemostaseologists and researchers. Gustav Born introduced the principle more than 40 years ago. Many different ways to perform aggregometry have been published. The results of aggregometry may become more comparable if some rules would be generally accepted. (1) The pre-analytical procedures are probably the most important factors which influence aggregometry results. Besides correct blood sampling important factors are the preparation of platelet-rich plasma (PRP), incubation of the PRP at room temperature and awareness of time-dependent changes of aggregometry results. (2) A major point concerns the agonists. Agonists of different sources have to be compared to verify that they lead to the expected results. Even different salts of ADP lead to different results and different collagen preparations lead to a large variation of aggregation response (3). The frequently used procedure of adjusting the platelet number in the PRP is cumbersome, affects platelet activation and is not necessary. (4) Aggregometers should comply with some simple rules. The changes in optical density should be linearized so that--if this is required--percentages can be given. The recorder speed should be standardized and all recorders should provide 1?cm/min. Calibration of the aggregometer sensitivity should be possible. (5) If aggregometry is used to define the response to antiaggregating agents agreement on the inducer concentrations is essential. If some rules are applied aggregometry is a relatively simple and reliable method, and well suited for clinical studies and for experimental research.

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

“…b Length of the lag phase (median score 8, range [5][6][7][8][9]. c Slope of aggregation (median score 7, range 3-9).…”

“…Ballots were blinded to the other members. The extreme scores (highest and lowest) were discarded, the median of the remaining scores was calculated and the area containing the majority of the ballots defined the classification of each statement about LTA practice: inappropriate (scores 1-3), uncertain (4-6) and appropriate (7)(8)(9).…”

“…Although popular and widely used, the LTA technique is not standardized [8], despite the fact that guidelines have been published [9][10][11]. Surveys organized by proficiency testing organizations identified variations in LTA practices and the need for guidelines to standardize LTA [12][13][14].…”

18F-GP1, a Novel PET Tracer Designed for High-Sensitivity, Low-Background Detection of Thrombi

“…The resulting IC 50 value represents the mean of 3 independent assays. The platelet aggregation assay was performed as described previously (23). Human plateletrich plasma was investigated after stimulus of adenosine diphosphate and platelet clumping recorded as a dynamic measure.…”

High prevalence of bleeders of unknown cause among patients with inherited mucocutaneous bleeding. A prospective study of 280 patients and 299 controls

“…In fact, when the same correlation analysis included only the 39 patients with isolated VWD as well as the non-bleeder controls, we then obtained similar results to Tosetto et al 29 There is a lack of standardization regarding the optimal number and agonist concentration of platelet functional tests. [7][8][9]30 Moreover, the influence of pre-analytical variables, types of samples and recording instruments, and the lack of consensus about agonist type and concentration and interpretation of results, tend to discredit study conclusions. To counteract these drawbacks, we standardized the assay considering all these factors.…”