ThromboLUX for determining platelet quality

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1 Updating information provided by the company October 2012 Horizon Scanning Centre October 2011 ThromboLUX for determining platelet quality SUMMARY Lay summary click here This briefing is based on information available at the time of research and a limited literature search. It is not intended to be a definitive statement on the safety, efficacy or effectiveness of the health technology covered and should not be used for commercial purposes or commissioning without additional information. ThromboLUX is a medical device designed to determine the quality and function of donated platelets during processing in the laboratory and before transfusing into a patient. Platelets are the cell particles within blood that help it clot, and transfusions may be needed to prevent or stop bleeding in people whose platelets are low in number, or ineffective. Results from the device are available in 15 minutes and are based on the principle of dynamic light scattering which is a Lightintegra method of measuring particle size, shape and response to temperature. The company states that use of ThromboLUX to screen platelets before they are transfused will reduce the number of potentially ineffective platelet transfusions given. BACKGROUND Platelets are small, irregular cell fragments within the bloodstream whose role is to help blood clot and prevent bleeding. Platelet transfusion can be used for patients who have low levels of platelets, or who have platelets that do not function properly. They may be used to treat bleeding, or be given to prevent bleeding from occurring in certain medical conditions 1. The main use of platelet transfusion is for people with cancers of the blood (such as leukaemia) who may have low platelets due to the disease or the chemotherapy needed to treat it. Platelets for transfusion can be prepared from donated whole blood or may be collected specifically from a donor (without taking away other blood cell components) in a process called plateletpheresis. Currently platelets are the third most frequently used blood component in the National Health Service in England 2. This briefing presents independent research funded by the National Institute for Health Research (NIHR). The views expressed are those of the author and not necessarily those of the NHS, the NIHR or the Department of Health. NIHR Horizon Scanning Centre, University of Birmingham nihrhsc@contacts.bham.ac.uk Web:

2 There were 19,179 admissions to hospital for platelet transfusion in England in (about 36 people per 100,000 population) 3. Approximately 247,000 adult doses of platelets were transfused in 2010 in the UK 2. As the price of an adult dose of platelets in the UK is around 230 this means that the NHS spends around 57,000,000 per year on platelets 4. CURRENT PRACTICE The quality of platelets supplied for transfusion is currently assured through a series of steps including selection of donors, validation of collection and processing procedures and analysis of a small sample of the batch for acidity. There are currently no standard, reliable tests for platelet quality 5. According to the British Committee for Standards in Haematology guidelines, prior to transfusion the bags containing platelet concentrates should be assessed visually for integrity of the pack, leaking or any unusual colour which may suggest bacterial contamination. The British Handbook for Transfusion Medicine does not refer to any specific test for platelet quality prior to transfusion 6. Failure to achieve the desired level of blood platelets in a patient following a transfusion (platelet transfusion refractoriness) occurs in 5-15% of chronic platelet recipients 7 and as many as 27% of all platelet recipients 8. There are many causes of platelet transfusion refractoriness, which are frequently attributable to patient factors such as fevers, enlarged spleen or medication. However, in some cases this will be due to poor platelet quality. NEW TECHNOLOGY Lightintegra has developed ThromboLUX, which uses the principle of dynamic light scattering to test the quality and function of a dose of platelets before transfusion. The test is intended for use in the hospital transfusion laboratory before the platelet bag is dispatched to be transfused. The device which carries out the test is comprised of a console and a disposable sampling set. A small sample is extracted from the platelet bag using the sterile sampling set which is then placed in the console. Results, which are ready in 15 minutes, are in the form of a quality score which ranges from Scores between 13 and 40 are believed to indicate that the platelets are of a suitable shape and functionality for transfusion with higher scores suggesting better functionality. Dynamic light scattering (also called photon correlation spectroscopy or quasi-elastic light scattering) is a method of determining the type, size, shape and concentration of particles in a platelet suspension as well as how they respond to temperature stress. Particles moving randomly through the suspension pass through a laser scattering the light in all directions. Different changes in scattered light are caused by the variation in particles; this is measured and used to determine the platelet size, shape and concentration in the sample. According to the company testing platelets prior to transfusing for platelet quality using their system may improve patient outcomes and safety and thereby potentially lower patient care costs. A CE mark for ThromboLUX is expected in January 2012, with UK launch following. The company intends to market it to hospital based transfusion services as well as blood collection centres. There are currently two devices being used on a research basis in England. The cost of ThromboLUX was not available for this briefing. 2

3 Company update on cost and NHS use October 2012 ThromboLUX TM is currently being evaluated in 11 European centres (including one UK NHS centre) with results expected this year. The price of ThromboLUX TM will be finalised once the evaluation is complete. The system is expected to be CE marked by the end of CLINICAL STUDIES AND RESEARCH QUESTIONS A study of 160 transfusions in 49 patients with blood cancers aimed to investigate whether the dynamic light scattering (DLS) score produced by ThromboLUX correlated with recovery and/or survival of transfused platelets in the body 9. The recovery and survival of platelets in the patients was assessed using changes in platelet counts (called correlated count increments, CCIs, which take into account body surface area and transfused dose). The one hour post transfusion CCI and 24 hour CCI reflect platelet recovery and survival in circulation, respectively. A statistically significant positive correlation was observed between DLS score and transfusion outcome (CCI1hr+CCI24hr, r=0.63, p<0.0001). ThromboLUX correctly identified 60% of transfusions which would have high platelet recovery and survival and 93% of those which would result in low platelet recovery and survival. A randomised controlled study which plans to enrol 200 participants is currently underway to assess whether the platelet survival (CCI24hr) of participants who receive platelets with a ThromboLUX score of over 15 differs significantly from that of people who receive any platelet concentrates regardless of ThromboLUX score (current standard of care) 10. The study is expected to be completed by July More randomised controlled trials which use the suggested DLS score of 12 as a cut off are needed to support the early findings of the ability of ThromboLUX to predict transfusion outcome. Evidence to date relates to recovery and survival of transfused platelets but not to their function, which is more likely to predict real clinical outcomes. Company update on trials October 2012 Maurer-Spurej E, Lee N, Nakane N et al. ThromboLUX donor screening for effective platelet transfusions. 32nd annual congress of the International Society of Blood Transfusion (ISBT). July Poster presentation P-171. Vox Sanguinis 2012;103(s1):120. Maurer-Spurej E and Leung J. Lipid interference in platelet quality testing. 32nd annual congress of the International Society of Blood Transfusion (ISBT). July Poster presentation P-175. Vox Sanguinis 2012;103(s1):121. 3

4 TECHNICAL DATA 9 ThromboLUX (n=99) Sensitivity 60% Specificity 93% PPV 71% NPV 90% POTENTIAL IMPACT If shown to be effective in predicting the outcome of platelet transfusion the ThromboLUX system may offer the first commercially available routine test for platelet quality which predicts platelet function after transfusion and this may be of interest to NHS blood transfusion services. This system would most probably be used at the point of production of platelets rather than just before transfusion. Benefits to the patient from avoidance of poor quality platelet transfusions may be that they reach the desired blood platelet level sooner and so reduce the time at risk from bleeding, and in some cases avoid delays for surgery where a particular platelet blood level is required. The cost in terms of money and staff time to implement the use of this test in the production of platelet doses for transfusion would need to be weighed against the potential cost savings from avoidance of transfusion of poor quality platelets and potentially improved clinical outcomes. Clear evidence on the effectiveness and cost- effectiveness of the ThromboLUX system will be needed before transfusion services would consider using it, as its use would lead to the discarding of precious bags of platelets on the basis of its results. 4

5 Lay summary The ThromboLUX system provides a new way of testing the quality of doses of platelets in the laboratory before they are sent out for transfusion. Platelets are small cell-like structures in blood which help it to clot and so prevent bleeding. People with some medical conditions, including blood cancers such as leukaemia, may have low levels of platelets and so be at risk from bleeding. In this case they can be given platelets from a blood donor. It just happens that sometimes these platelets may be poor quality, and at the moment it is difficult to find that out for sure. This new system may allow the blood transfusion laboratory to do extra testing on all the doses of platelets so they can make sure only the high quality ones are sent out for patients. Early studies show that the ThromboLUX system may be promising, but more studies are needed to show whether it works well enough to be useful in the NHS. REFERENCES 1 British Committee for Standards in Haematology. Guidelines for the use of platelet transfusions. British Journal of Haematology, 2003; 122: Serious Hazards of Transfusion. Annual Report Manchester: SHOT; July NHS. NHS England HES data Qureshi H, Lowe D, Dobson P et al. National comparative audit of the use of platelet transfusions in the UK. Transfusion Clinique et Biologique. 2007;14: NHS Blood and Transplant. National Commissioning of blood, components and specialists services. 2010/11. Accessed on 24 October McClelland DBL editor. Handbook of Transfusion medicine United Kingdom Blood Services 4 th Edition. London: The Stationary Shop; Rebulla P. A mini-review on platelet refractoriness. Haematologica 2005;90: Slichter SJ, Davis K, Enright H et al. Factors affecting post transfusion platelets increments, platelet refractoriness, and post transfusion intervals in thrombocytopenic patients. Journal of Transfusion Medicine 2005;105(10): Maurer-Spurej E, Labrie A, Pittendreigh C et al. Platelet quality measured with dynamic light scattering correlates with transfusion outcome in hematologic malignancies. Transfusion 2009;49: Current Controlled Trials. Comparison of in vivo outcome following transfusion of dynamic light scattering-screened versus unscreened platelets. Accessed 24th October