Characterization of Platelet Concentrates Using Dynamic Light Scattering

Abstract

Background: Each year, millions of platelet transfusions save the lives of cancer patients and patients with bleeding complications. However, between 10 and 30% of all platelet transfusions are clinically ineffective as measured by corrected count increments, but no test is currently used to identify and avoid these transfusions. ThromboLUX® is the first platelet test intended to routinely characterize platelet concentrates prior to transfusion. Methods: ThromboLUX is a non-invasive, optical test utilizing dynamic light scattering to characterize a platelet sample by the relative quantity of platelets, microparticles, and other particles present in the sample. ThromboLUX also determines the response of platelets to temperature changes. From this information the ThromboLUX score is calculated. Increasing scores indicate increasing numbers of discoid platelets and fewer microparticles. ThromboLUX uses calibrated polystyrene beads as a quality control standard, and accurately measures the size of the beads at multiple temperatures. Results: Results from apheresis concentrates showed that ThromboLUX can determine the microparticle content in unmodified samples of platelet concentrates which correlates well with the enumeration by flow cytometry. ThromboLUX detection of microparticles and microaggregates was confirmed by microscopy. Conclusion: ThromboLUX provides a comprehensive and novel analysis of platelet samples and has potential as a non-invasive routine test to characterize platelet products to identify and prevent ineffective transfusions.

Refrigeration and cryopreservation of platelets differentially affect platelet metabolism and function: a comparison with conventional platelet storage conditions

“…22 Our results reflect this finding, with the cold-stored and cryopreserved PLTs having a lower score and fewer discoid PLTs than those stored at room temperature, as shown by microscopy. Traditionally, the Kunicki morphology score has been used to assess the number of discoid versus spherical PLTs in a sample.…”

“…In contrast, the DLS score combines all of these aspects, as well as the response to temperature stress to provide a score that has shown potential in estimating the in vivo efficacy of fresh liquidstored PLTs before transfusion. 22,39,40 While cold-stored PLTs had a lower DLS score than those stored at room temperature, all units maintained a score greater than 12, for up to 14 days of storage, which has been associated with better corrected count increments at 1 hour posttransfusion. 39,40 The lower score is likely partially reflective of the increase in microparticles, and while the algorithm assumes that microparticles are undesirable in PLT components, we have previously shown that they may actually provide a hemostatic benefit.…”

“…39,40 The lower score is likely partially reflective of the increase in microparticles, and while the algorithm assumes that microparticles are undesirable in PLT components, we have previously shown that they may actually provide a hemostatic benefit. 16,21 The DLS score is also influenced by the response of PLTs to temperature stress 22 and may be indicative of posttransfusion efficacy, as is HSR, 25 which indicates membrane stress. As such, the relationship between these variables was investigated and a strong positive correlation was found between the HSR and DLS score of PLTs over storage (r 5 0.8500; p < 0.0001).…”

“…The DLS score was generated using the manufacturer's analysis software (ThromboSight, Version 3.03, LightIntegra Technologies). 22 The pH, blood gases, and lactate content of PLT components were measured using a blood gas analyzer (i-STAT, Abbott Point of Care, Inc.), in conjunction with the CG41 cartridges (Abbott Point of Care, Inc.). These variables were measured at 378C, and bicarbonate was calculated by the i-STAT analyzer from the pH and pCO 2 values.…”

Could Microparticles Be the Universal Quality Indicator for Platelet Viability and Function?

“…The optical system, small sample volume, and specific software used in ThromboLUX address the challenges other DLS instruments face with testing platelet-rich plasma or platelet concentrates [20, 43]. The qNano Gold (Izon Science) uses size exclusion chromatography and resistive pulse sensing [47], and a combination of dynamic light scattering and particle tracking is used by NanoSight (Malvern) [48].…”