Storage of buffy coat preparations at 22 degrees C in plastic containers with different gas permeability

Process improvement by eliminating mixing of whole blood units after an overnight hold prior to component production using the buffy coat method

The elimination of a thorough manual mixing of whole blood (WB) which takes place following the overnight hold, but before the first centrifugation step, during buffy coat component production at Canadian Blood Services (CBS) was investigated. WB was pooled after donation and split. Pairs of platelet, red blood cell (RBC), and plasma components were produced, with half using the standard method and half using a method in which the mixing step was eliminated. Quality assessments included yield, pH, CD62P expression and morphology for platelets, hemoglobin, hematocrit, hemolysis, and supernatant K⁺ for RBCs, and volume and factor VIII activity levels for plasma. All components, produced using either method, met CBS quality control criteria. There were no significant differences in platelet yield between components produced with and without mixing. A significant difference was seen for RBC hemolysis at expiry (P = 0.03), but for both groups, levels met quality control requirements. Noninferiority of components produced without mixing was confirmed for all parameters. Manual mixing is laborious and has a risk of repetitive strain for production staff and its significance is unclear. Elimination of this step will improve process efficiencies without compromising quality.

Noninvasive pH Monitoring in Platelet Concentrates

BACKGROUND

New technology introduces the option to measure pH in platelet concentrates noninvasively. Findings that in one out of 25 apheresis concentrates the pH decreased significantly during storage motivated us to evaluate apheresis concentrates from 307 platelet donors.

METHODS

Small (15 ml) BSCI storage containers for noninvasive pH measurement were used in parallel with Fenwal PL2400 bags for storage of 5 days. Noninvasive pH measurement was compared to pH determination in samples from the storage container. Decrease of pH during storage was calculated as ΔpH d2-d5.

RESULTS

The coefficient of correlation for noninvasive pH measurement (n = 256) versus standard methods was R(2) = 0.964 (pH electrode) or 0.952 (ABL 510). pH values in BSCI bags were slightly lower than in Fenwal PL2400 containers. Concentrates collected from 8 of the 307 donors showed a significant drop in pH. Repeated collection did not confirm these findings with a single exception.

CONCLUSION

Noninvasive pH measurement demonstrates a high reproducibility. Our study could not confirm the frequency of 1 out of 25 plateletpheresis donors with concentrates developing a significant drop in pH during storage. This may be due to a substantially lower platelet concentration in our preparations.

In vitro platelet quality in storage containers used for pediatric transfusions

BACKGROUND

The in vitro quality of small-volume platelet (PLT) aliquots for pediatric transfusions was assessed to determine the best practice approach.

STUDY DESIGN AND METHODS

Small volumes (50 mL) of single apheresis PLT components (APCs), collected on either CaridianBCT Trima or Haemonetics MCS+ instruments, were aliquoted on Days 2, 3, 4, and 5 postcollection into Fenwal PL1240 or 4R2014 bags or 60-mL polypropylene syringes. Samples were tested for in vitro quality at their recommended expiry times (4 hr for 4R2014 bags and syringes or Day 5 for PL1240 bags). Assays included pH, CD62P expression, and metabolic measures.

RESULTS

CD62P expression increased throughout storage in all containers. Among the small-volume containers, pH, pCO(2) , lactate, and bicarbonate varied considerably. Regardless of the day of aliquoting, pCO(2) was significantly higher and pO(2) was significantly lower in gas-impermeable syringes than other containers. No bacterial growth was detected in any sample.

CONCLUSION

The quality of APCs aliquoted into small-volume containers meets regulatory requirements and is generally equivalent to that of full-volume APCs at expiry.

Impact of sample volume and handling time during analysis on the in vitro quality measurements of platelet concentrates held in syringes

INTRODUCTION

The determination of quality parameters is a necessity for monitoring the efficacy of platelet concentrates. During consolidated quality control studies, there may be a large number of samples to be analyzed at the same time. This common workflow setup triggered the question whether there is an influence of the number of samples to be analyzed on the accuracy of the test results.

METHODS

Two different sample volumes of platelet concentrates, 1 ml and 50 ml, were analyzed for a set of standard in vitro parameters including pCO(2), pO(2), pH, glucose, and lactate as well as platelet activation via CD62P expression and responsiveness to adinosine diphosphate in an extent-of-shape-change assay. To assess apoptotic mechanisms triggered by the hold time, changes in the phosphatidylserine exposure were monitored.

RESULTS

In total, eleven time points were assessed over a 3-h period as well as an overnight point for assay evaluation. Except for pCO(2) and pO(2), all in vitro parameters analyzed were unaffected by a sample hold time of up to 3-h.

CONCLUSION

Sampling for pO(2) determination should be carried out in small volumes and assessed within 30 min of collection to obtain reliable and comparable results.

Short-term liquid storage of CD14+ monocytes, CD11c+, and CD123+ precursor dendritic cells produced by leukocytapheresis

BACKGROUND

This prospective study compared white blood cell (WBC) storage in polyvinylchloride (PVC) bags and in polyolefin (POF) bags. After leukapheresis, CD14+ monocytes, CD11c+, and CD123+ precusor dendritic cells (DCs) were analyzed under platelet (PLT) storage conditions.

STUDY DESIGN AND METHODS

Twenty-five leukapheresis procedures were performed on blood cell separators (AS.TEC204 [PVC; Fresenius HemoCare GmbH] and the COBE Spectra [POF, Gambro BCT]). Blood cell counts, glucose, lactic acid, pO(2), pCO(2), and pH were measured in mononuclear cell (MNC) harvests on Days 0, 1, 3, and 5. WBCs were analyzed by flow cytometry.

RESULTS

The WBC yields of the AS.TEC204 harvests were 25 percent higher (13.4 x 10(9) +/- 2.7 x 10(9) WBCs) compared to the COBE Spectra (9.9 x 10(9) +/- 2.5 x 10(9) WBCs). During 5-day storage, WBC counts (PVC bags) decreased significantly (24%). Storage in POF bags showed more consistent results (WBC loss, 6%). Loss of CD14+ monocytes and CD11c+ precursor DCs did not differ significantly in leukapheresis products. CD123+ precursor DCs stored in PVC bags dropped by more than 90 percent (POF bags, 24%). Lactic acid concentrations exceeded 20 mmol per L after 24 hours in PVC bags and after 72 hours in POF bags. The mean pH value on Day 5 was 6.2 (PVC) and 6.3 (POF). On Day 1, the product glucose concentration decreased by 76 percent after storage in PVC bags and by 16 percent in POF bags.

CONCLUSIONS

Storage of MNCs within 72 hours in the original harvest container assures stable WBC content and is easy to perform. POF bags should be preferred in the case of extended WBC storage. Patient studies should clarify changes in efficiency of hematopoietic reconstitution that might occur over time during MNC storage.

Storage of blood components

Recent studies have shown that a restrictive transfusion policy results in lower mortality in patients undergoing surgery. The negative effects of red cell transfusion are associated with the presence of contaminating leukocytes, leukocyte products, and probably also with effects of nonviable and poorly functioning red cells. By relatively simple means it is possible to improve the quality of red cells in these respects. The removal of leukocytes from platelet concentrates (PCs) is even more important because of high immunogenicity and capacity to produce cytokines under the storage conditions applied. Prestorage leukocyte removal has clear advantages. Bacterial contamination of PCs is common, but fatal bacterial complications are rare because most contaminating microorganisms grow slowly and do not produce toxins, which are frequent causes of death. Suitable methods for routine bacterial culture of PCs are available and used in some countries.

International forum: Europe. Buffy-coat-derived platelet concentrates: Swedish experience

The need for source material for plasma products such as factor VIII preparations and improving the quality of red cells for transfusion became determining factors in the choice of methods for blood components in the 1970s and 1980s in Sweden. The possibility to make platelet concentrates (PC) from buffy coats (BC-PC) instead of from platelet-rich plasma (PRP-PC), as first described in England and The Netherlands, using an additive solution as the major component of the platelet storage medium, as first described by Rock et al., has been shown to influence favourably the national supply of blood components and has become accepted as the normal standard procedure in the first half of the 1990s. Leucocyte-depleted PCs, produced from pools of 4-6 BCs, used in all multiple platelet transfusions to thrombocytopenic patients, have strongly reduced the demand for HLA compatible PCs. Nationwide, 79% of the demand of PCs is supplied as BC-PCs, mostly leuco-depleted which, so far, have compared favourably with apheresis-PCs for cost-effectiveness.