Critical re-appraisal of blood component quality after overnight hold of whole blood outside current room temperature limits.

BACKGROUND AND OBJECTIVES: According to European guidelines, the temperature of whole blood (WB) has to be maintained at 20-24°C until processing within 24 h, but in blood bank practice, WB is frequently held at temperatures between 18-25°C. We aimed to assess the impact of these small temperature deviations on the quality of the blood components. MATERIALS AND METHODS: After rapid cooling, 7 WB units were held overnight at 18°C and 8 units at 25°C, reflecting worst case holding conditions, and separated into a red cell concentrate (RCC), plasma and buffy coat (BC). RCCs were filtered at test temperature and stored for 42 days at 2-6°C. BCs were processed to single-BC platelet concentrates (sPC) and stored up to Day 8 at 20-24°C. RESULTS: After overnight hold at 18°C, 2,3-DPG in WB decreased by 34 ± 9%, while at 25°C the decrease was 82 ± 6%. Accordingly, the 2,3-DPG levels in the RCCs in the 25°C group were significantly lower than in the 18°C group (2·2 ± 1·4 vs. 10·4 ± 2·9 µmol/g Hb). RCCs and sPCs in the 25°C group showed higher initial lactate levels and lower pH compared to the 18°C group, but these differences levelled off at the end of storage. RCCs showed small differences in ATP levels and haemolysis. Plasma in both groups showed comparable Factor VIII:C levels. CONCLUSION: The temperature of WB during overnight hold strongly affects initial 2,3-DPG levels of RCCs and supports the maintenance of temperature limits between 20 and 24°C. Other in vitro effects of the temperature deviations were small and of no practical relevance.

Alternatives in blood operations when choosing non-DEHP bags.

The use of di-ethylhexyl-phthalate (DEHP) in blood bags is under discussion due to toxicity concerns and possible restrictions. A questionnaire among 15 blood centres in nine countries showed that none so far have fully switched to non-DEHP blood bags. If centres had to change, sites with a 42-day outdate would choose for a shorter outdating period, while others would allow a higher haemolysis rate (but within current specifications). To improve red cell quality, about half of the centres are willing to move to an alternative red cell storage solution, while the other half would not change for various reasons.

Serum eye drops: a survey of international production methods.

BACKGROUND: Serum eye drops (SEDs) are used to treat dry eye syndrome and non-healing corneal lesions when other treatments fail. Despite many clinical studies demonstrating the efficacy of both autologous and allogeneic SEDs, there is no internationally harmonized method for producing SEDs. MATERIALS AND METHODS: A 40-question survey requesting information regarding donor selection, blood collection and processing, infectious disease screening, shelf life and regulatory requirements for the production of autologous and allogeneic SEDs was developed by the Biomedical Excellence for Safer Transfusion Collaborative. Survey data were collected into a database via a secure web interface and then downloaded into Excel for further analysis. RESULTS: A total of 55 responses were received, with 21 responses from centres indicating they produce SEDs. Based on the responses, collection and processing practices differ widely, according to the size of the centre making the SEDs, and their ability to collect, process and test the blood. CONCLUSION: Despite divergences in the methods for producing SEDs, the end result is a small-volume aliquot of serum that can be administered by a patient at home. If more centres move from producing autologous to allogeneic SEDs, this may provide an opportunity for production methods to become more standardized internationally.

Experiences with semi-routine production of riboflavin and UV-B pathogen-inactivated platelet concentrates in three blood centres.

BACKGROUND: For a clinical platelet (PLT) transfusion trial conducted in three countries, the production of PLT concentrates (PCs) that were pathogen inactivated with the Mirasol technology was set up and validated. While the Mirasol procedure is applied to an established PLT product, the PLT processing procedure still had to be modified to ensure a treated PC was of sufficient quality. Further, the effect of simulated transport conditions and the effect of ambient light on Mirasol-treated PCs was determined. STUDY DESIGN AND METHODS: Platelet concentrates in plasma were made from pooled buffy coats followed by Mirasol treatment. To mimic transport conditions, units were left unagitated for 6 h at room temperature. To mimic ambient light exposure, units were held unagitated for 4 h in direct fluorescent tube light. RESULTS: Measures had to be taken to allow 7-day storage of treated concentrates. In one site, PCs made from five buffy coats with >450 × 109 PLTs were removed from inventory. Another site went from five to four buffy coats per pool. Interruption of agitation for 6 h on day 3 did not induce meaningful changes in in vitro measures, even when stored up to 7 days. Exposure to ambient light for 4 h, either on day 3 or 6, had no effect on in vitro measures. CONCLUSION: The Mirasol pathogen inactivation process can be implemented in routine, but changes to current PLT processing methods might be needed. Transport conditions and 4-h-long ambient light exposure have no negative effect on the in vitro quality of Mirasol-treated PCs.

Comparison of haemostatic function of PAS-C-platelets vs. plasma-platelets in reconstituted whole blood using impedance aggregometry and thromboelastography.

BACKGROUND AND OBJECTIVES: There are concerns about the haemostatic function of platelets stored in platelet additive solution (PAS). Aim of this study was to compare the haemostatic function of PAS-C-platelets to plasma-platelets in reconstituted whole blood. MATERIALS AND METHODS: In our experiment, whole blood was reconstituted with red blood cells, solvent-detergent (SD) plasma and either PAS-C-platelets or plasma-platelets (n = 7) in a physiological ratio. On storage days 2, 5, 8 and 13, the agonist-induced aggregation (multiple electrode aggregometry), clot formation (thromboelastography) and agonist-induced CD62P responsiveness (flow cytometry) were measured. RESULTS: Samples with PAS-C-platelets showed significantly lower aggregation than plasma-platelets when induced with adenosine diphosphate, -6 U (95% confidence interval: -8; -4) or thrombin receptor-activating protein, -15 U (-19; -10). Also when activated with collagen and ristocetin, the PAS-C-platelets showed less aggregation, although not statistically significant. All samples with PAS-C-platelets showed significantly lower agonist-induced CD62P responsiveness than samples with plasma-platelets. However, there was no difference regarding all TEG parameters. CONCLUSION: Our findings demonstrate that the function - aggregation and CD62P responsiveness - of PAS-C-platelets in reconstituted whole blood is inferior to that of plasma-platelets, which may have implications in the setting of massive transfusions.

Evaluation of the role of the GPIb-IX-V receptor complex in development of the platelet storage lesion.

BACKGROUND AND OBJECTIVES: In mice, loss of sialic acid resulting in shedding of glycoprotein (GP) Ibα and GPV has been linked to platelet survival. The aim of this study was to determine whether loss of sialic acid and the GPIb-IX-V complex contributes to development of the platelet storage lesion (PSL) in human platelet concentrates (PCs). MATERIALS AND METHODS: PCs (stored in plasma (with or without Mirasol treatment); PAS-C or PAS-E) were stored at room temperature. Flow cytometry was used to monitor membrane expression of the GPIb-IX-V complex, CD62P, surface glycans and PS exposure. The functionality of stored platelets was determined employing aggregometry and ristocetin-induced VWF binding. RESULTS: Storage time of PCs in blood banks is limited to 7 days. During this time period, a minor but gradually increasing subpopulation of GPIbα-negative platelets was observed. Also, ristocetin-induced VWF binding was impaired in a small population of platelets. Mean surface expression of GPIbα and GPV remained stable until day 9, whereas CD62P expression increased; also a rapid decrease in ADP-induced aggregation was observed for PAS-C, PAS-E and Mirasol-treated PCs. Upon prolonged storage (>9 days), a slow decline in surface expression of GPIbα and GPV was observed; no major changes were observed in surface sialylation with the exception of Mirasol-treated platelets. CONCLUSION: In a small population of stored platelets, changes in GPIbα occur from day 2 onwards. Loss of sialic acid and subsequent shedding of GPIbα and GPV is not an early event during the development of the PSL.

Effect of increased agitation speed on pathogen inactivation efficacy and in vitro quality in UVC-treated platelet concentrates.

BACKGROUND AND OBJECTIVES: Pathogen inactivation technologies require continuous development for adjustment to different blood components and products. With Theraflex UV-Platelets, a system using shortwave ultraviolet C (UVC) light (254 nm), efficient mixing of platelet concentrates (PCs) during UVC treatment is essential to ensure homogeneous illumination of the blood components. In this study, we investigated the impact of increasing the agitation speed during UVC treatment on pathogen inactivation capacity and platelet quality. MATERIAL AND METHODS: The pathogen inactivation efficacy of UVC treatment was evaluated at two agitation speeds (110 vs. 180 rpm) using four different transfusion-relevant bacteria strains and three model viruses. Using a pool-and-split design, the in vitro quality of buffy coat-derived PCs stored in SSP+ additive solution for up to 7 days was assessed in UVC-treated PCs agitated at either 110 rpm (standard speed) or 180 rpm (increased speed) and in untreated controls. RESULTS: The higher agitation speed improved bacterial inactivation but did not influence viral inactivation. Metabolic activity (glucose consumption and lactate accumulation) in UVC-treated platelets was slightly higher than in untreated controls. Increases in parameters such as CD62P expression and annexin A5 binding indicated moderate activation of UVC-treated platelets. Quality variables for UVC-treated platelets agitated at standard vs. increased agitation speed were comparable. CONCLUSION: The mixing rate during illumination may be a process parameter for further development of UVC-based pathogen inactivation procedures for PLT concentrates.

PAS or plasma for storage of platelets? A concise review.

Platelet additive solutions (PASs) are becoming increasingly popular for storage of platelets, and PAS is steadily replacing plasma as the storage medium of platelets. PASs are electrolyte solutions intended for storage of platelets, and they are used to modulate the quality of the platelets by adding specific ingredients. All currently available PASs contain acetate. Acetate reduces the amount of glucose that is oxidised into lactic acid and thereby prevents the lowering of pH, which decreases platelet quality. Furthermore, the oxidation of acetate leads to the production of bicarbonate, which serves as buffer. The presence of potassium and magnesium in PAS prevents the lowering of pH and reduces the degree of spontaneous activation of the platelets during storage. In the hospital, platelets stored in PAS result in about half of the number of allergic transfusion reactions as compared with platelets in plasma. Recovery and survival after transfusion, as well as corrected count increments, are at least as good for platelets in PAS as for plasma, and recent data suggest they may even be better. Therefore, with the current generation of PASs, PAS should be preferred over the use of plasma for the storage of platelet concentrates.

Commercially available blood storage containers.

Plastic blood bags improve the safety and effectiveness of blood component separation and storage. Progress towards optimal storage systems is driven by medical, scientific, business and environmental concerns and is limited by available materials, consumer acceptance and manufacturing and regulatory concerns. Blood bag manufacturers were invited to submit lists of the bags they manufacture. The lists were combined and sorted by planned use. The lists were analysed by experts to assess the degree to which the products attend to scientific problems. Specific issues addressed included the use of di-ethylhexyl phthalate (DEHP) as plasticizer for polyvinyl chloride (PVC) blood bags, the size, material and thickness of platelet bags, and the fracture resistance of plasma bags. Alternatives to DEHP for red blood cell (RBC) storage exist, but are mostly in a developmental stage. Plastic bags (DEHP-free, PVC-free) for platelet storage with better gas diffusion capabilities are widely available. Alternatives for plasma storage with better fracture resistance at low temperatures exist. Most RBC products are stored in DEHP-plasticized PVC as no fully satisfactory alternative exists that ensures adequate storage with low haemolysis. A variety of alternative platelet storage systems are available, but their significance - other than improved oxygen transport - is poorly understood. The necessity to remove DEHP from blood bags still needs to be determined.

Separation of centrifuged whole blood and pooled buffy coats using the new CompoMat G5: 3 years experience.

BACKGROUND AND OBJECTIVES: Semi-automatic separation devices can be used for the separation of centrifuged whole blood into leucoreduced red cell concentrate (LR-RCC), plasma and buffy coat (BC) and to make platelet concentrates (PC) from pooled BCs. To improve and to obtain a more uniform and standardized process, the CompoMat G5 (Fresenius) was implemented, a new-generation semi-automated device. MATERIALS AND METHODS: Uniform programs for WB separation and preparation of PCs were validated, using collection and pooling systems with CompoFlow (CF) closures, which can be automatically opened by the G5. Cell counts were performed and compared with historic data of blood components obtained with the formerly used Compomat G4 and Optipress II. After implementation, different adjustments were made to improve product quality. RESULTS: Leucoreduced red cell concentrates (280 ± 15 ml, 53 ± 5 g haemoglobin) and plasma (317 ± 16 ml) met European guidelines. BCs (48 ± 2 ml, 0·42 ± 0·05 l/l, 93 ± 25 × 10(9) platelets) contained a similar platelet (PLT) content as BC prepared before with the Compomat G4. A relatively high percentage (4-6%) of PCs (330 ± 17 ml, 330 ± 50 × 10(9) PLT, 0·12 ± 0·21 × 10(6) leucocytes) contained <250 × 10(9) PLT which was the subject of improvement studies. After implementation, RCC and BC discard decreased and workload was less. Operator complaints were also less frequent. CONCLUSION: The same high-quality blood components can be prepared by using the CompoMat G5 as previously with other semi-automated devices. Improvement was realized by automation of the opening process by the use of collection systems with CF closures, which led to a decrease in discarded units and workload.

Counting platelets at transfusion threshold levels: impact on the decision to transfuse. A BEST Collaborative - UK NEQAS(H) International Exercise.

BACKGROUND AND OBJECTIVES: Obtaining accurate and precise platelet enumeration in automatic platelet analysers at low platelet counts is a challenge. To explore the performance of current haematology analysers in counting platelet concentrations usually used as platelet transfusion threshold. MATERIAL AND METHODS: An international exercise where four blood samples with platelet levels near usual platelet transfusion thresholds was prepared and distributed. RESULTS: The samples shipped had a platelet count of 6·3, 13·3, 21·6 and 53·0 × 10(9) /l according to the international reference method. We received 82 sets of results from nine countries. Instruments from six different manufacturers were represented. Although the mean count for each of the four samples was very similar to the values, according to the reference method (9·0, 16·2, 23·0 and 57·6 × 10(9) /l), significant variability in the results was found. Assuming that these were patient samples and the result of the count used to indicate a prophylactic platelet transfusion, undertransfusion would have occurred for 24·5% of the LP1 samples at a transfusion threshold of 10 × 10(9) /l and, at a threshold of 20 × 10(9) /l, undertransfusion would have occurred for 7·2% of the LP1 and 16·2% of the LP2 samples and overtransfusion would have occurred with 23·1% of the LP3 samples. CONCLUSION: The results suggest that significant inaccuracy exists in counting low levels of platelets and that this inaccuracy might have a significant impact in under- and overtransfusion of platelet concentrates to patients.

Development of a mitochondrial DNA real-time polymerase chain reaction assay for quality control of pathogen reduction with riboflavin and ultraviolet light.

BACKGROUND AND OBJECTIVES: Transfusion is associated with a risk of infection and alloimmunization. Pathogen reduction using riboflavin and UV light (Mirasol treatment) inactivates pathogens and leucocytes. With increasing adoption of the technology in clinical use, regulatory agencies have recommended the introduction of quality control measures to monitor pathogen reduction efficacy. We sought to develop a real-time PCR-based assay to document the impact of pathogen reduction on the mitochondrial genome in blood components. MATERIALS AND METHODS: DNA was extracted from platelet and plasma components before and after treatment with riboflavin and UV light. Inhibition of PCR amplification of mitochondrial DNA (mtDNA) in short- and long-amplicon target regions, ranging from under 200 base pairs (bp) to over 1800 bp, was measured in treated relative to untreated components. RESULTS: Pathogen reduction of platelets using riboflavin and UV light resulted in inhibition of PCR amplification of long-amplicon mtDNA targets, demonstrating approximately 1 log reduction of amplification relative to untreated products. Amplification of short-amplicon mtDNA targets was not affected by treatment. Evaluation of 110 blinded platelet samples from the PREPAReS clinical trial resulted in prediction of treatment status with 100% accuracy. Pathogen reduction of plasma components resulted in similar levels of PCR inhibition, while testing of 30 blinded plasma samples resulted in prediction of treatment status with 93% accuracy. CONCLUSION: A differential sized amplicon real-time PCR assay of mitochondrial DNA effectively documents nucleic acid damage induced by Mirasol treatment of platelets. The use of the assay for plasma product pathogen reduction requires further investigation.

Measuring clinical bleeding using a standardized daily report form and a computer algorithm for adjudication of WHO bleeding grades.

INTRODUCTION: Bleeding is increasingly considered an important end point in clinical platelet transfusion studies. Accurate recording and adjudication into well-defined bleeding grades, however, remains a major challenge. METHODS: We developed a computer algorithm for automatic adjudication. The algorithm's results were compared to those of three independent adjudicators. RESULTS: For one of 1186 bleeding days, the clinical report form (CRF) was filled out incorrectly, and the algorithm therefore missed one grade-1 skin bleed. For two bleeding days, the adjudicators incorrectly classified a grade-2 skin bleed as grade-1 while the algorithm correctly classified these days. The algorithm saved approximately six person-hours of adjudication time for the adjudication of 1186 days from 60 patients. DISCUSSION: The algorithm can be an invaluable tool for adjudicating large amounts of bleeding data.

The observation of bleeding complications in haemato-oncological patients: stringent watching, relevant reporting.

BACKGROUND: The reported percentage of haemato-oncological patients experiencing bleeding complications is highly variable, ranging from 5 to 70%, posing a major problem for comparison of clinical platelet transfusion trials using bleeding complications as a primary endpoint. In a pilot study we assessed the impact of the design of scoring of bleeding on the percentage of patients with WHO grade 2 or higher bleeding grades. STUDY DESIGN AND METHODS: We performed a prospective, observational study using a rigorous bleeding observation system in thrombocytopenic patients with haemato-oncological disorders. Endpoints of the study were the percentage of patients and days with bleeding WHO grade ≥ 2 comparing designs in which skin bleeding represent a continuation of a previous bleed or a new bleed. RESULTS: In four participating hospitals 64 patients suffering 870 evaluable thrombocytopenic days (platelet count < 80 × 10(9) L(-1)) were included. At least one episode of bleeding grade ≥ 2 occurred in 36 patients (56%). Most grade 2 bleeding complications occurred mucocutaneously. The percentage of days with bleeding of grade ≥ 2 was 16% but decreases to 8% when only newly developed skin bleeding was included. CONCLUSION: Rigorous daily observation results in a bleeding incidence that is comparable to recent reportings applying the same method. The results of this study show that censoring for stable skin bleeding has a profound effect on bleeding incidence per day. The clinical relevance of rigorous or clinically judged bleeding scores as an endpoint remains to be defined.

Platelet concentrates from fresh or overnight-stored blood, an international study.

BACKGROUND: Whole blood and also buffy coats (BCs) can be held for a few hours or overnight before processing into blood components or platelet concentrates (PCs). Individual studies have reported a range of outcomes regarding in vitro variables for PCs prepared from fresh and stored whole blood. In this multicenter study, effects of storage of whole blood or BCs on the in vitro quality of PCs were studied. STUDY DESIGN AND METHODS: The leukoreduced BC PCs were prepared from fresh BCs (2-8 hr after collection; fresh/fresh), from BCs at 20 to 24 hours after collection (fresh/stored), or from BCs prepared from whole blood stored for 20 to 24 hours (stored/fresh). PCs were stored on a flat-bed shaker at 20 to 24°C for 7 days. PCs were tested on Days 0 (only fresh/fresh), 1, 5, and 7 for in vitro quality. There were six participating centers that tested all three conditions with n = 6 per condition. RESULTS: In comparison to fresh/stored and stored/fresh PCs, fresh/fresh PCs exhibited a lower platelet (PLT) count (Day 1-220 × 10(9) ± 70 × 10(9) vs. 324 × 10(9) ± 50 × 10(9) and 368 × 10(9) ± 56 × 10(9) PLTs/PC), lactate, pCO(2), and hypotonic shock response (HSR; Days 5 and 7; Day 7-50 ± 13% vs. 57 ± 12 and 63 ± 11%) and a higher pH, glucose, pO(2), and CD62P expression (than stored/fresh PCs only; Day 7-33 ± 10% vs. 28 ± 12 and 24 ± 11%; p < 0.05). No differences were observed for volume, swirling effect, white blood cell count, annexin V binding, or aggregation between these conditions. CONCLUSION: Based on PLT count, HSR, and PLT activation, PCs are best prepared after 20 to 24 hours hold of the whole blood or BCs.

Coagulation factor content of plasma produced from whole blood stored for 24 hours at ambient temperature: results from an international multicenter BEST Collaborative study.

BACKGROUND: There is increasing international interest in producing components from blood that has been stored at room temperature for 24 hours. The lack of comprehensive data on the quality of plasma produced from blood stored in this way led to this international study. STUDY DESIGN AND METHODS: A total of 128 units of whole blood were pooled in groups of four and split to produce 32 sets of four identical blood units that were processed either within 8 hours of blood collection or after 24-hour storage at 18 to 25°C. RESULTS: Storage of whole blood for 24 hours resulted in a 23% decrease in the activity of Factor (F)VIII, but not significant loss of activity of coagulation factors FV, FVII, FXI, FXII, fibrinogen, antithrombin, or von Willebrand factor. There was a small, but significant decrease in levels of FII, FIX, and FX (all <5%) as well as protein C (6%) and free protein S activity (14%). The ability of plasma to generate thrombin after 24-hour storage as whole blood was unaltered, as assessed by real-time thrombin generation tests as was the rate and strength of clot formation by rotational thombelastometry. Levels of all coagulation factors measured were above 0.50 U/mL in plasma produced from whole blood stored for 24 hours. CONCLUSION: These data show that there is minimal effect of storing whole blood at ambient temperature for 24 hours on the coagulation activity of plasma and that this is an acceptable alternative to producing plasma on the day of blood collection.

Effect of rate and delay of cooling during initial cooling process: in vitro effect on red cells.

BACKGROUND: Whole blood is stored at room temperature (RT) until processing into components. After separation and filtration, the RCC has to be cooled from RT to +2 - 6°C. Different start times of the cooling process and different cooling rates can be encountered in daily routine. The effect of these parameters of the initial cooling of leucoreduced red cell concentrates (LR-RCC) on in vitro quality is not known. METHODS: In paired experiments (n=12), LR-RCCs in SAGM were cooled immediately after preparation from RT to +2 to +6°C either 'fast' (within 2½ h) or 'slow' (within 10-24 h) or 'slow' after a holding period of 6, 12, 18 or 24 h. Units were then stored at +2-6°C for 42 days and sampled at regular intervals for in vitro analysis. RESULTS: Irrespective of the start time and cooling rate during the initial cooling process, all units maintained good in vitro quality up to Day 42 with haemolysis <0·8%. Adenosine triphosphate (ATP) levels remained >2·7 µmol/g Hb in 99% of all units up to Day 35. Differences in pH, ATP content and 2,3-DPG content between the groups were largest at Day 2 or 3 but generally disappeared during storage. CONCLUSION: Start time and cooling rate of the initial cooling process had minor effects on in vitro quality of red cells. LR-RCCs can be stored up to 24 h before cooling down to +2-6°C without deleterious effects on in vitro parameters during 42-day storage.

In vitro comparison of platelet storage in plasma and in four platelet additive solutions, and the effect of pathogen reduction: a proposal for an in vitro rating system.

BACKGROUND: The introduction of platelet (PLT) additive solutions (PASs) and pathogen reduction (PR) technologies possibly allow extension of PLT shelf life. It was our aim to compare in vitro quality of leucocyte-reduced PLT concentrates (PCs) stored in various PASs, including PR, with those in plasma during 8 days of storage. The study was performed in four blood centres where each tested four conditions. STUDY DESIGN AND METHODS: In paired experiments (n = 12), buffy coat pools were made to which various storage media were added. Plasma served as reference; two centres used InterSol followed by PR (InterSol+PR) and InterSol without PR; T-sol, SSP+ and Composol were also studied. RESULTS: All PCs fulfilled release criteria (pH(37 degrees C)>6.6; swirl present) until Day 8. Marked differences were seen for other parameters, including CD62P expression: 28 +/- 5; 31 +/- 7; and 39 +/- 9% for T-sol, Intersol+PR and without PR, respectively, which were higher as found for Composol (12 +/- 3%), SSP+ (15 +/- 5%) and plasma (15 +/- 6%). Three parameters (CD62P, Annexin A5, and lactate concentration) were collapsed into one rating value (6 = good quality, 0 = poor quality); PLTs in plasma had a rating of 2.8 +/- 1.0, which was higher as for T-Sol (1.5 +/- 0.5), InterSol+PR (1.3 +/- 0.6) and without PR (1.7 +/- 0.5). PLTs in potassium- and magnesium-containing PASs showed higher ratings as plasma, 4.3 +/- 0.5 for Composol and 3.8 +/- 0.8 for SSP+. CONCLUSION: PLT concentrates in plasma, SSP+ and Composol scored better using an arbitrary rating system as PLTs stored in T-Sol or InterSol; PR further impaired rating parameters. The applicability of these differences in rating for clinical effects needs a clinical study.