Frequent platelet donation is associated with lymphopenia and risk of infections: A nationwide cohort study.

BACKGROUND: Recently, plateletpheresis donations using a widely used leukoreduction system (LRS) chamber have been associated with T-cell lymphopenia. However, clinical health consequences of plateletpheresis-associated lymphopenia are still unknown. STUDY DESIGN AND METHODS: A nationwide cohort study using the SCANDAT3-S database was conducted with all platelet- and plasmapheresis donors in Sweden between 1996 and 2017. A Cox proportional hazards model, using donations as time-dependent exposures, was used to assess the risk of infections associated with plateletpheresis donations using an LRS chamber. RESULTS: A total of 74 408 apheresis donors were included. Among donors with the same donation frequency, plateletpheresis donors using an LRS chamber were at an increased risk of immunosuppression-related infections and common bacterial infections in a dose-dependent manner. While very frequent donors and infections were rare in absolute terms resulting in wide confidence intervals (CIs), the increased risk was significant starting at one-third or less of the allowed donation frequency in a 10-year exposure window, with hazard ratios reaching 10 or more. No plateletpheresis donors that used an LRS chamber experienced a Pneumocystis jirovecii, aspergillus, disseminated mycobacterial, or cryptococcal infection. In a subcohort (n = 42), donations with LRS were associated with low CD4+ T-cell counts (Pearson's R = -0.41; 95% CI, - 0.63 to -0.12). CONCLUSION: Frequent plateletpheresis donation using an LRS chamber was associated with CD4+ T-cell lymphopenia and an increased risk of infections. These findings suggest a need to monitor T-lymphocyte counts in frequent platelet donors and to conduct future investigations of long-term donor health and for regulators to consider steps to mitigate lymphodepletion in donors.

Adopting a vein assessment tool improves procedural outcomes in double dose platelet collections - A prospective study.

BACKGROUND: This study aims to determine the phlebotomy and procedural outcomes using a vein assessment tool (VAT) in Double Dose Platelet (DDP) collections by apheresis. METHODS: VAT was based on assessing vein visibility, palpation and size with maximum score of 12 and the least being 0 and the scores were graded as adequate and inadequate. A vein-viewer was used for studying cubital vein patterns (type 1-5). Phlebotomy outcome was defined based on need for re-puncture. Procedural outcomes in terms of target yield attained and RBC reinfusion completed. Chi square test and Mann- Whitney U test were used to assess the vein score and pattern against phlebotomy and procedural outcome. RESULTS: Out of 200 DDP collections, the phlebotomy was successful in 88 % with good procedural outcome in 94 % donations. The cut off in VAT scores for successful phlebotomy was ≥8 (AUC: 70 %). Median vein scores of the arm selected for phlebotomy was 9 and graded adequate in 154 (77 %) donations.Odds for successful phlebotomy was 3.7 times higher when donors had an adequate VAT grades(p = 0.003). Procedural outcomes was favourable when at least one arm had adequate VAT grade when compared to both arms being inadequate (98 % vs 82 %; p < 0.001). Phlebotomy failure was more with first time apheresis donors than repeat apheresis donors (p = 0.014). CONCLUSION: This study indicated that a VAT score with a cut off of ≥8 had better phlebotomy and procedural outcomes in DDP collections and that donor with at least one arm having the VAT score of ≥8 are preferred for DDP collections.

A comparative study of five plateletpheresis machines in a tertiary care center of India: AmiCORE vs COM.TEC vs Haemonetics MCS+ vs Spectra Optia vs Trima Accel.

BACKGROUND: Single donor apheresis platelets are superior in quality, but their usage is limited in a developing country due to cost and time constraints. Hence the product obtained must exceed in terms of yield, donor safety and technical convenience. Previous literature available on cell separators is on older versions. AIMS: Prospective comparison of 5 latest cell separators (AmiCORE, COM.TEC, Haemonetics MCS+, SpectraOptia and TrimaAccel) for product yield, performance variables and donor adverse effects. MATERIAL & METHODS: From October 2019 - March 2020, 1108 donors were randomly allotted to a cell separator. Post-donation sample was taken from the donor 15-20 minutes after procedure completion. The platelet yield from the product collected was measured twice (day 0 and day 1). Donor demography, pre-and post-procedural donor peripheral blood values, performance and product variables were statistically analyzed. RESULTS: AmiCORE had an optimal collection efficacy (44.6%) and collection rate (0.037 x 1011/minute). Haemonetics MCS+ had a better collection efficacy (48.4%) and rate (0.038 x 1011/minute). Spectra Optia achieved least procedural time (59.5 minutes), donor adverse effects (6.3%); highest collection efficacy (52.8%) and rate (0.056 x 1011/minute). Trima Accel achieved highest collection rate (0.056 x 1011/minute) and the least product volume (228 ml). CONCLUSION: Highest collection efficacy was achieved by Trima Accel, highest collection rate by Trima Accel and Spectra Optia, lowest donor adverse effects by Spectra Optia and least number of procedural troubleshooting by COM.TEC. Apart from this, fiscal factors and service availability also need to be considered before choosing a cell separator.

The impact of delayed and immediate adverse events on the intention of future donations in whole blood and plateletpheresis donors.

BACKGROUND: Adverse donor events (ADEs) are usually mild and short-term with no sequelae, but may cause disinclination toward future donations. AIMS: To determine the impact of delayed ADEs (D-ADEs) in addition to immediate ADEs (I-ADEs) on the intention of future donations (IFDs) and to analyze the various associated factors. METHODS: ADEs were categorized following the ISBT working group on donor vigilance. Telephonic interviews of the donors were conducted 2 weeks after the whole blood (WB) and plateletpheresis donation to inquire about D-ADEs and IFDs. RESULTS: A total of 3514 WB and 531 plateletpheresis donors were included in the study. WB donors had an overall higher IFD as compared to plateletpheresis donors (89.53% vs 57.06%, P < .001). A higher IFD was observed in male WB donors as compared to female WB donors (89.95% vs 75%, P < .001). Repeat WB donors had a higher IFD as compared with first-time donors (93.66% vs 81.37%, P < .001). A total of 13.7% WB donors and 19.2% plateletpheresis donors reported D-ADEs. WB donors who experienced D-ADEs had a significantly lower IFD (78.38% vs 91.63%, P < .001) as compared with donors without any ADEs; a similar trend was observed in donors who experienced I-ADEs (69.90% vs 91.63%, P < .001). In WB donors, systemic D-ADEs such as fatigue had a more negative impact on IFDs as compared with localized D-ADEs such as bruises (63.93% vs 86.83%, P < .001). CONCLUSIONS: Both D-ADEs and I-ADEs negatively impact donors' intention to donate again. Systemic D-ADEs had a more negative impact on IFDs as compared with localized D-ADEs.

Severe CD4+ T-cell lymphopenia is not observed in frequent plateletpheresis donors collected on the Fenwal Amicus.

BACKGROUND: In a recent study, we determined that 30% of frequent plateletpheresis donors collected using the Trima Accel Automated Blood Collection System (Terumo BCT) had a CD4+ T-cell count below 200 cells/µL. Whether CD4+ T-cell lymphopenia is associated with donation using other plateletpheresis instruments is unknown. STUDY DESIGN AND METHODS: We obtained blood samples from 30 current frequent Fenwal Amicus plateletpheresis donors. All participants had made 20 to 24 plateletpheresis donations in the most recent 365-day period, and all had previously donated over 50 times on the Fenwal Amicus instrument. Blood samples were analyzed to determine blood counts, including CD4+ and CD8+ counts. RESULTS: Of 30 study participants, none had a CD4+ count below 200 cells/µL. There was one participant with a CD4+ count between 200 and 300 cells/µL. This individual was over the age of 55 and had a history of more than 300 lifetime plateletpheresis sessions. One participant had a CD8+ count below the lower limit of normal (125 cells/µL) and a normal CD4+ count. CONCLUSION: We did not detect severe CD4+ lymphopenia in frequent platelet donors undergoing plateletpheresis with the Fenwal Amicus. Since the Fenwal Amicus does not incorporate a leukoreduction system chamber, this finding supports the hypothesis that such chambers-found in the Trima Accel instrument-contribute to CD4+ lymphopenia in frequent platelet donors.

Apheresis technology correlates with bacterial contamination of platelets and reported septic transfusion reactions.

BACKGROUND: Apheresis technology to collect platelet (PLT) components differs among devices. We evaluated the relationship of the plateletpheresis device with bacterial contamination and reported septic transfusion reactions. STUDY DESIGN AND METHODS: Plateletpheresis was performed using Amicus (Fenwal, a Fresenius Kabi Company) or Trima (Trima Accel, TerumoBCT) from 2010 to 2014. All donations used inlet-line sample diversion and were tested by quality control (QC; Day 1) aerobic culture. Rates of bacterial contamination and septic reactions to PLTs were calculated for both devices. RESULTS: During the 5-year study period, plateletpheresis collections using Amicus and Trima devices totaled 1,486,888 and 671,955 donations, respectively. The rate of confirmed-positive bacterial cultures of apheresis PLT donations was significantly higher with Amicus than with Trima (252 vs. 112 per 106 donations [odds ratio {OR}, 2.3; 95% confidence interval {CI}, 1.8-2.9]). Septic transfusion reactions were caused by 30 apheresis PLT units from 25 contaminated Amicus procedures and three apheresis PLT units from three contaminated Trima procedures. The overall rate of septic reactions was significantly higher with apheresis PLT components collected with Amicus than with Trima (16.8 vs. 4.5 per 106 donations [OR, 3.8; 95% CI, 1.1-12.5]). All apheresis PLT components implicated in septic transfusion reactions had negative QC culture results incubated through Day 5 (i.e., false negatives). CONCLUSION: Apheresis technology affects bacterial contamination of plateletpheresis collections. The device-specific, higher rate of confirmed-positive bacterial culture results also correlated with a significantly higher rate of reported septic transfusion reactions to apheresis PLTs.

Safety and feasibility of therapeutic platelet depletion with Spectra Optia in a pregnant woman.

INTRODUCTION: Thrombocytapheresis is an alternative treatment beneficial in rare circumstances, when cytoreductive agents are contraindicated, drug therapy gave no response or the expected response would be too slow. Here we present a case of a pregnant woman who underwent 5 thrombocytaphereses using Spectra Optia device to reduce circulating platelets (PLT) count and prepare for Cesarian section. PATIENT CHARACTERISTICS AND PERFORMED TREATMENT: A 39-year-old woman with diagnosed chronic myeloid leukemia (CML) was treated with interferon because of too high PLT count. The treatment was well tolerated but the effect was not satisfactory (PLT count remained high). Because of high risk of bleeding during childbirth, the healthcare providers decided to perform thrombocytapheresis to reduce circulating PLT count below 1000×10E3/µl, and to prepare the patient for a planned Cesarean section. The results are presented as mean±SD. RESULTS: Five therapeutic aphereses procedures were performed, with a Spectra Optia device (TerumoBCT). A mean of 1.3±0.3 total blood volume was processed and we observed a mean PLT drop of 42.3±17.7%. Each apheresis procedure resulted in a PLT level ≤1000×10E3/µl. PLT CE1 was high 50.6±2.6% and reproducible. The white blood cell (WBC) loss was low (18.5%±11.0%). No adverse effects were observed. CONCLUSION: Therapeutic platelet depletion using the Spectra Optia™ Apheresis System can be effective and safe during pregnancy. Thrombocytapheresis procedures were reproducible and Spectra Optia system successfully adjusted settings to each procedure conditions. Thrombocytapheresis seems to be a viable and safe option even in pregnant women.

Plateletpheresis efficiency and mathematical correction of software-derived platelet yield prediction: A linear regression and ROC modeling approach.

BACKGROUND: Advances in automated cell separators have improved the efficiency of plateletpheresis and the possibility of obtaining double products (DP). We assessed cell processor accuracy of predicted platelet (PLT) yields with the goal of a better prediction of DP collections. STUDY DESIGN AND METHODS: This retrospective proof-of-concept study included 302 plateletpheresis procedures performed on a Trima Accel v6.0 at the apheresis unit of a hematology department. Donor variables, software predicted yield and actual PLT yield were statistically evaluated. Software prediction was optimized by linear regression analysis and its optimal cut-off to obtain a DP assessed by receiver operating characteristic curve (ROC) modeling. RESULTS: Three hundred and two plateletpheresis procedures were performed; in 271 (89.7%) occasions, donors were men and in 31 (10.3%) women. Pre-donation PLT count had the best direct correlation with actual PLT yield (r = 0.486. P < .001). Means of software machine-derived values differed significantly from actual PLT yield, 4.72 × 1011 vs.6.12 × 1011 , respectively, (P < .001). The following equation was developed to adjust these values: actual PLT yield= 0.221 + (1.254 × theoretical platelet yield). ROC curve model showed an optimal apheresis device software prediction cut-off of 4.65 × 1011 to obtain a DP, with a sensitivity of 82.2%, specificity of 93.3%, and an area under the curve (AUC) of 0.909. CONCLUSION: Trima Accel v6.0 software consistently underestimated PLT yields. Simple correction derived from linear regression analysis accurately corrected this underestimation and ROC analysis identified a precise cut-off to reliably predict a DP.

Platelet corrected count increments by apheresis platform.

BACKGROUND: Automated blood collection platforms use different technological systems to isolate and collect individual blood components. These unique systems could potentially result in differences in platelet in vivo viability, as measured by the corrected count increment (CCI). STUDY DESIGN AND METHODS: This retrospective study evaluated CCI data of platelet transfusions among oncology patients who received multiple unmanipulated apheresis platelets between January 1, 2006 and December 31, 2009. Apheresis platelets were collected from our community blood center by standard procedures using two different collection systems and were transfused to patients in a blinded manner. RESULTS: The CCI of the platelet recipient was significantly higher at 0-2 hours post-transfusion among the individuals who received platelets collected on Trima Accel (Terumo BCT) (mean = 6281, standard deviation = 3650) compared to the platelets collected by the Amicus system (Fresenius Kabi) (mean = 5251, standard deviation = 3311, p = 0.004). CONCLUSIONS: These hypothesis-generating data suggesting improved recovery and survival of Trima Accel platelets demonstrate the need for the investigation and implementation of the best collection methods to provide better platelet transfusion support.

Washing of platelets can be fully automated using a closed-system cell processor and BRS-A platelet additive solution.

This study evaluated the in vitro properties of platelets (PLTs) washed with BRS-A additive solution in the Haemonetics ACP215 automated processing system. Two washing modes, 'manually/automatically adding ACD-A to BRS before/during the washing process', represented the control and test groups, respectively. Outcomes were compared over 7 days of storage (n = 7, for both). PLT recovery following washing processing (26-27 min) was 86·2 ± 1·7% and 86·0 ± 2·2% and plasma protein removal was 98·8 ± 0·3% and 99·0 ± 0·2% in the control and test groups, respectively (not significant). Both groups exhibited comparable in vitro properties.

Effectiveness of the Trima Accel cell separator in the double dose plateletpheresis.

The use of apheresis equipment to collect blood components has rapidly increased in the past years. A variety of apheresis instruments are now available on the market for double dose plateletpheresis. We evaluated an apheresis instrument, the Trima Accel, with regard to platelet (PLT) yield, collection efficiency (CE), and collection rate (CR) in a retrospective, randomized study in 110 donors. The Trima Accel cell separator efficiently collected double dose platelets with median PLT yields of 3.7 × 1011, mean CE of 74.99 ± 14.40% and mean CR of 0.096 ± 0.012 × 1011/min.

Evidence of meaningful levels of Trypanosoma cruzi in platelet concentrates from seropositive blood donors.

BACKGROUND: According to the reported cases of transfusion-acquired Trypanosoma cruzi infection, the risk of T. cruzi transfusion transmission appears to be higher with platelet (PLT) products than with other blood components. The aim of this study was to investigate by quantitative real-time polymerase chain reaction (qPCR) the parasitic load detected in leukoreduced plasma and PLT concentrates collected by apheresis from seropositive T. cruzi blood donors and compare them with peripheral whole blood (WB). STUDY DESIGN AND METHODS: During 2011 to 2013, a prospective study was carried out in a group of blood donors originating from Chagas-endemic areas but who are now living on the island of Majorca, Spain. Leukoreduced plasma and PLT concentrates were collected by apheresis from seropositive blood donors with detectable parasitemias in peripheral WB. RESULTS: Seropositivity was found in 23 of 1201 donors studied (1.9%), and T. cruzi DNA with less than 1 parasite equivalent/mL was detected in peripheral WB in 60.86% (14 of 23) of these. The study in blood components obtained by apheresis from these donors showed that T. cruzi DNA with a mean ± SD parasitic load of 5.33 ± 6.12 parasite equivalents/mL was detected in 100% of the PLT concentrate samples. Parasite DNA was undetectable in the extract taken from plasma collected from donors with a positive qPCR in peripheral WB. CONCLUSION: The higher parasitic load found in PLT concentrates compared to plasma and peripheral WB would explain the higher transfusion transmission risk of Chagas disease associated with PLT transfusions described in the reported cases of transfusion-acquired T. cruzi infection.

Effectiveness of the haemonetics MCS cell separator in the collection of apheresis platelets.

Platelet (PLT) transfusions play an important role in patients with thrombocytopenia or severely impaired platelet function. Platelet concentrates are prepared from whole-blood donations or by plateletpheresis. In recent years, different instruments have been developed to perform plateletpheresis. We evaluated an apheresis instrument, the Haemonetics MCS(®) + with regard to PLT yield, collection efficiency (CE), and collection rate (CR) in a retrospective, randomized study in 526 donors. In this system, we used leukoreduction filters post collection to obtain leukoreduced products. The Haemonetics MCS(®) + cell separator efficiently collected apheresis platelets with median PLT yields of 3.7 × 10(11), mean CE of 66.69 ± 13.73% and mean CR of 0.063 ± 0.013 × 10(11)/min. The median blood volume processed was 3290 (2420-4370) ml, and the median volume of acid citrate dextrose-A (ACD-A) used in collections on the device was 385 (196-517) ml. Also, this device allowed the collection of white blood cell (WBC) reduced plateletpheresis with mean 0.07 ± 0.15 × 10(6) WBC content. No serious donor or recipient reactions occurred.

Practical issues that should be considered when planning the implementation of pathogen reduction technology for plateletpheresis.

Pathogen reduction technology (PRT) is associated with increased blood safety through the inactivation of virus, bacteria and parasites. Dilution of platelet (PLT) concentrates in platelet additive solution (PAS) is a requirement for applying PRT, and that it is associated with various practical issues: increasing PLT target yields to compensate for loss of PLTs through PRT, extended apheresis donation time due to PAS addition at the end of the procedure, and the appearance of PLT aggregates. We proposed to program higher target PLT yields for plateletpheresis donations to compensate for PLTs lost due to PRT processing. To verify the feasibility of this approach, a paired study of the Amicus 3.11 and Trima 5.22 apheresis separators was performed using 196 procedures carried out on the same 98 donors. The Amicus 3.11 presented a higher collection efficiency (CE: 78.02 vs. 69.63; p < 0.0001) and collection rate (CR: 8.3 vs. 7.00; p < 0.0001); it was also faster (56.92 vs. 62.60; p < 0.0001) than the Trima 5.22 apheresis device. However, analysis of the donor group with higher pre-procedure PLT counts showed similar productivity results for the Amicus and Trima. The percentage of PLT aggregates detected was higher with the TA than the AM (8.62% vs. 3.88%, p = 0.04). Overall, both separators are entirely suitable for collecting hyper-concentrated PLTs that are subsequently diluted in PAS for PRT, without excessively increasing the donation time. PLT aggregation can occur after apheresis collection but most of them disappear by day 1. Further investigation is needed to study the clinical impact of PLT aggregation.

Improvement of plateletpheresis via technical modification on the MCS+.

BACKGROUND: With the advantage of easy operation and high reliability, Haemonetics multicomponent collection system (MCS+) is widely used as a blood cell separator in clinical application. OBJECTIVES: The aim of this study was to evaluate the effect of technical parameter modification as utilised on the MCS+ to improve the quality of platelet yielded as well as donor comfort. METHODS: After informed consent, a total of 118 donors, well matched for baseline parameters, were included in the study from December 2012 to April 2013. Sixty-one donors underwent single-dose plateletpheresis (SDP), and the other 57 donors underwent double-dose plateletpheresis (DDP) before and after technical modification on the MCS+, respectively, according to the manufacturer's instructions. The procedures were evaluated, focusing on whole blood processed (WBP), processing time (PT) and number of cycles were measured, as well as the quality of products. RESULTS: No severe adverse reaction was found during donation. WBP, PT and number of cycles after modification were all reduced significantly in both SDP and DDP groups (P < 0·01). In addition, 80·51 % (95 in 118) of the total post-modification products were qualified, presenting with high quality. Besides, the comfort of donors was also improved probably because of the reduced PT. CONCLUSION: Adjustment of the relevant technical parameters on MCS+ could produce a beneficial effect on the procedure measures and ensure a high-quality platelet production.

Comparison of plateletpheresis on the Fenwal Amicus, Fresenius COM.TEC, and Trima Accel Cell separators.

Blood component donations by apheresis have become more common in modern blood transfusion practices. We compared three apheresis instruments (Fenwal Amicus, Fresenius COM.TEC, and Trima Accel) with regard to platelet (PLT) yield, collection efficiency (CE), and collection rate (CR). The single-needle or double-needle plateletpheresis procedures of the three instruments were compared in a retrospective, randomized study in 270 donors. The blood volume processed was higher in the COM.TEC compared with the Amicus and Trima. Also there was a significantly higher median volume of ACD used in collections on the COM.TEC compared with the Amicus and Trima. The PLT yield was significantly lower with the COM.TEC compared with the Amicus and Trima. Additionally, the CE was significantly lower with the COM.TEC compared with the Amicus and Trima. There was no significant difference in median separation time and CR between the three groups. When procedures were compared regarding CE by using Amicus device, it was significantly higher in single-needle than double-needle plateletpheresis. When double-needle Amicus system was compared with double-needle COM.TEC system, CE and PLT yield were significantly higher with Amicus system. When single-needle Amicus system was compared with single-needle Trima system, CE and PLT yield were significantly higher with Trima system. All instruments collected PLTs efficiently. However, the CE was lower with the COM.TEC compared with the Amicus and Trima. Also, we found Amicus single-needle system collected PLTs more efficiently compared with the double-needle system. CE and PLT yields were significantly higher with the single-needle Trima instrument compared with the single-needle Amicus device.

Reduced use of allogeneic platelets through high-yield perioperative autologous plateletpheresis and reinfusion.

BACKGROUND: Intraoperative autologous platelet (PLT) collection as part of a multimodal blood conservation program carries a Class IIa recommendation from the Societies of Thoracic Surgeons and Cardiovascular Anesthesiologists, but achieving a suitable PLT yield limits its application. A novel, autologous, intraoperative, high-yield plateletpheresis collection program was established and retrospectively analyzed to identify potential improvements over previously reported plateletpheresis protocols. STUDY DESIGN AND M-ETHODS: Targeting complex cardiothoracic surgery patients without recent anti-PLT agents, thrombocytopenia, or severe anemia, the program aimed to achieve a PLT yield of at least one standard apheresis unit (3.0 × 10(11) ) within 60 to 90 minutes and using an automated plateletpheresis device (Trima, Terumo BCT). Anesthetized and invasively monitored patients underwent plateletpheresis via a large-bore, indwelling central line placed for the surgery. Collection-related data for quality control purposes and subsequent PLT transfusion requirements were analyzed and reported. RESULTS: Forty-two patients donated autologous PLTs between 2011 and 2012. PLT yield was 4.5 (3.9-5.0) × 10(11) , which significantly exceeds previously reported yields, and procedure duration was 53.2 (48.4-57.9) minutes. As anticipated, postcollection PLT count decreased from 268 (242-293) × 10(9) to 182 (163-201) × 10(9) /L; hypocalcemia was minimized by infusion of 1 g of CaCl2 . Autologous PLT yield was inversely correlated with allogeneic PLT use, and avoidance of allogeneic PLT transfusion was increased when the autologous yield was the equivalent of 2 or more apheresis units. CONCLUSION: High-yield, intraoperative autologous PLT collection is achievable using an automated plateletpheresis device. Initial experience shows a reduction in reliance on allogeneic PLTs for complex cardiothoracic surgery.

Bacterial culture of apheresis platelets: a mathematical model of the residual rate of contamination based on unconfirmed positive results.

BACKGROUND: Platelet septic reactions result from low concentrations of bacteria that escape detection by quality-control BacT/ALERT™ culture testing. We estimate the contamination rate with these bacteria at the time of testing using a mathematical model. METHODS: Culture results and reported septic reactions are described for platelets collected between January 2007 and December 2011. Initial positive results with negative confirmatory cultures were reclassified assuming some of the 'unconfirmed positive results' represent collections contaminated with low-concentration, dormant bacteria. A mathematical model based on the probability of the detection of bacteria describes the upper limit of the residual rate of contamination. RESULTS: The rate of confirmed or unconfirmed positive apheresis platelet donations was 188 per million (1:5317) and 110 per million (1:9124), respectively. The rate of post-transfusion sepsis and reported fatalities per distributed component was 1:106 931 and 1:1 015 843, respectively. A linear decrease in unconfirmed positive Bacillus spp. cultures most likely reflected diminishing environmental contamination over time. The remaining unconfirmed positive results identified similar bacteria species as those associated with septic reactions. Assuming that these represent contamination of the collection with low-concentration, dormant bacteria, the model identified a residual contamination of 3524-204 per million (1:284-1:4902) for collections contaminated with 1-20 bacteria, respectively. DISCUSSION: Greater than 99·5% of collections contain no viable, aerobic bacteria in solution at the time of early culture testing. For every confirmed positive contaminated collection detected, there are at most 19 collections with low concentrations of dormant bacteria that are not readily detected by early BacT/ALERT™ culture.

Quality assessment of buffy-coat-derived leucodepleted platelet concentrates in PAS-plasma, prepared by the OrbiSac or TACSI automated system.

BACKGROUND AND OBJECTIVES: Buffy-coat (BC)-derived platelet concentrates (PCs) are the predominant product for platelet transfusion in many countries. Two automated systems, OrbiSac and TACSI, have been introduced in blood centres to prepare these PCs, as an alternative to the manual method. We compared the in vitro quality of PCs prepared by both methods during standard storage. STUDY DESIGN AND METHODS: Twenty primary BC pools were split into two parts, which were processed with OrbiSac and TACSI system to obtain OrbiSac PCs (O-PCs) and TACSI PCs (T-PCs), respectively. On days 1, 5 and 7 of standard storage, samples were taken and the following analysed: cell count, metabolic variables, platelet function and content of activation and proinflammatory substances. RESULTS: Both the OrbiSac and TACSI systems produced PCs that meet the standards for platelet products in terms of platelet and leucocyte content. In vitro evaluation pointed to the similar preservation of platelet metabolism (pH, glucose, bicarbonate and lactate) in O-PCs and T-PCs. Moreover, there were no significant differences between O-PCs and T-PCs as regards the hypotonic shock response or in the platelet aggregation profile. The OrbiSac system caused greater platelet activation, which resulted in higher concentrations of sCD62P, RANTES and sCD40L on the day the PCs were prepared. CONCLUSION: The systems OrbiSac and TACSI can be used to produce buffy-coat-derived PCs whose cell content, platelet function and metabolism are similar during standard storage. However, the preparation with the OrbiSac system induces a transient increase in platelet activation and release of proinflammatory substances.

Residual aggregates in platelet products: what do we know?

BACKGROUND AND OBJECTIVES: Platelet (PLT) aggregates can occur during or after PLT component processing. However, very few reports investigating the phenomenon and its clinical significance have been published. In this review, currently available information about aggregates in PLT products is summarized and possible causal factors as well as preventive strategies are discussed. MATERIALS AND METHODS: A review of the MEDLINE® database for relevant publications from 1960 to May 2013 was conducted. RESULTS: It is well known that PLT aggregates may occur during or after the PLT product preparation process. These aggregates normally dissipate with rest and agitation. However, in some rare cases, the aggregates do not dissipate within 24 h and can persist up to the end of storage. Exposure to low temperature, low pH, short resting period after collection, different collection systems, presence of bubbles or foam inside the PLT bag, PLT-container interactions, proper product mixing and donor-dependent variables may have an impact on the formation of PLT aggregates. Although publications are rare, the presence of small numbers of PLT aggregates appears to have only limited impact on PLT in vitro quality. Furthermore, data on the clinical impact of PLT aggregates are lacking. CONCLUSION: Despite the fact that PLT aggregates occur in PLT products, published data on this topic remain scant. Considering the concern of clinicians about this phenomenon, more studies are needed which should focus on the possible clinical impact of such aggregates and precautions to avoid PLT aggregate formation in PLT products.