Improvement of plasma quality as raw material for factor VIII:C concentrates. Storage of whole blood and plasma and interindividual plasma levels of fibrinopeptide A

Assays for Qualification and Quality Stratification of Clinical Biospecimens Used in Research: A Technical Report from the ISBER Biospecimen Science Working Group

This technical report presents quality control (QC) assays that can be performed in order to qualify clinical biospecimens that have been biobanked for use in research. Some QC assays are specific to a disease area. Some QC assays are specific to a particular downstream analytical platform. When such a qualification is not possible, QC assays are presented that can be performed to stratify clinical biospecimens according to their biomolecular quality.

Factor VIII and fibrinogen recovery in plasma after Theraflex methylene blue-treatment: effect of plasma source and treatment time

BACKGROUND

The quality of fresh-frozen plasma is affected by different factors. Factor VIII is sensitive to blood component storage processes and storage as well as pathogen-reduction technologies. The level of fibrinogen in plasma is not affected by the collection processes but it is affected by preparation and pathogen-reduction technologies.

MATERIALS AND METHODS

The quality of plasma from whole blood and apheresis donations harvested at different times and treated with a pathogen-reduction technique, methylene blue/light, was investigated, considering, in particular, fibrinogen and factor VIII levels and recovery.

RESULTS

The mean factor VIII level after methylene blue treatment exceeded 0.5 IU/mL in all series. Factor VIII recovery varied between 78% and 89% in different series. The recovery of factor VIII was dependent on plasma source as opposed to treatment time. The interaction between the two factors was statistically significant. Mean levels of fibrinogen after methylene blue/light treatment exceeded 200 mg/dL in all arms. The level of fibrinogen after treatment correlated strongly with the level before treatment. There was a negative correlation between fibrinogen level before treatment and recovery. Pearson's correlation coefficient between factor VIII recovery and fibrinogen recovery was 0.58.

DISCUSSION

These results show a difference in recovery of factor VIII and fibrinogen correlated with plasma source. The recovery of both factor VIII and fibrinogen was higher in whole blood plasma than in apheresis plasma. Factor VIII and fibrinogen recovery did not appear to be correlated.

Protein composition of clots detected in pooled cryoprecipitate units

BACKGROUND

On rare occasions, upon thawing of stored cryoprecipitate components, clots are observed on visual inspection. Although it has been assumed that the clot reflects fibrinogen to fibrin conversion, there are few published studies that document that this assumption is correct. Our studies were conducted to further identify the protein characteristics of the clotted material.

STUDY DESIGN AND METHODS

Clotted material isolated from four thawed cryoprecipitate pools was examined by solubilization procedures and electrophoresis analysis.

RESULTS

Solubilization of much of the clotted material in phosphate-buffered saline warmed to 37°C suggested the presence of soluble fibrin. Gel electrophoresis under reducing conditions showed that the most prevalent bands exhibited molecular weights corresponding to the α, β, and γ subunits of fibrinogen with a much lighter band exhibiting the molecular weight of fibrinogen γ-γ dimer, consistent with the presence of partially crosslinked fibrin. The presence of the dimer indicated that the clotted material was caused by the action of thrombin, but also reflected the action of Factor XIIIa. No ongoing clot formation was observed.

CONCLUSION

Our studies indicate that, on rare occasions, fibrinogen conversion to fibrin is responsible for observable clots in thawed cryoprecipitate pools. These clots are structurally heterogeneous, including both noncrosslinked (soluble) and crosslinked (insoluble) fibrin. This diversity in the fibrin structure may account for some of the diversity in the limited literature regarding their presence in cryoprecipitate pools.

A comparative study of the effects of temperature, time and factor VIII assay type on factor VIII activity in cryoprecipitate in Iran

BACKGROUND

In Iran, cryoprecipitate is an important plasma product to provide coagulation factors such as factor VIII (FVIII) in patients with factor VIII deficiency. FVIII is one of the labile coagulation factors and as such is also used as a quality marker of fresh-frozen plasma and cryoprecipitate. It is, therefore, important to optimise plasma production in order to prevent a reduction of FVIII activity. In this study we assessed the effect of temperature, time and FVIII assay type on FVIII activity in cryoprecipitate produced in Iran.

METHODS

Ninety-six whole blood units were kept at two different temperatures (48 units kept at 1-6 °C and 48 kept at 20-24 °C) for periods of 4, 6, 8 or 10 hours before plasma freezing. FVIII activity was then measured by both chromogenic and one-stage clotting assays.

RESULTS

At both temperatures, FVIII activity in plasma prepared after 8 and 10 hours was lower than that in plasma prepared after 4 and 6 hours. A significant decrease of FVIII activity was not seen in samples kept for 4 and 6 hours. Compared to storage between 1-6 °C, storage at 20-24 °C appears to cause a reduction in FVIII activity. There was a significant difference in apparent FVIII activity measured by the one-stage clot-based and chromogenic assays.

CONCLUSION

In Iran, to improve cryoprecipitate quality, freezing should begin within 6 hours after donation and whole blood should be kept at 1-6 °C until the plasma can be frozen. In this study although a good correlation was seen between the results of the one-stage clot-based and chromogenic assays for measuring FVIII activity in cryoprecipitate, the absolute values were significantly different.

Storage of whole blood for up to 24 hours at ambient temperature before component preparation: implementation in the Netherlands

The aim of this article is to reflect on the historical background on what urged the authors in the 1980s to investigate the prolonged storage of whole blood at ambient temperature before component preparation, the routine implementation of the method in the Netherlands, and the effect on logistics and plasma procurement.

Quality of plasma for fractionation--does it matter?

Many plasmapheresis techniques cause greater activation of platelets, complement and coagulation than does simple whole blood collection. Activation of the coagulation cascade has been particularly evident in tests for potential thrombogenicity in prothrombin complex concentrates made from apheresed plasma. Attempts to improve the factor VIII content and fractionation yield of source plasma have centred on rapid freezing, increased concentration of anticoagulants and the exploitation of anticoagulants optimal for the preservation of coagulant, rather than cellular, activities. The cumulative advantage is of the order of 10% over recovered plasma. There are potential pitfalls in applying low-citrate anticoagulation strategies to plasmapheresis. Recalcification of citrated plasma, under cover of an optimal concentration of heparin, might be explored more vigorously.

Preservation of factor VIII activity in plasma by different freezing techniques, as determined with a chromogenic microtray assay

The preservation of factor VIII activity in frozen plasma was studied using three different freezing techniques. Two were conventional methods, i.e. ethanol bath at -40 degrees C, and deep-frozen at -80 degrees C, and the third was a novel air-based -40 degrees C freezer with metal compartments and snugly fitting flat 750 ml plasma containers. No statistically significant difference in preservation of factor VIII was observed, irrespective of freezing technique, as determined with a chromogenic substrate assay.

A simple and accurate microplate assay for the determination of factor VIII activity

Based on the CoatestR Factor VIII kit, a simple and accurate microtiter plate assay has been developed. The method has been simplified through the combination of the bovine factors IXa + X, phospholipid and calcium chloride into one reagent. A further improvement was obtained by generating F Xa to a stable plateau level, thus minimizing influences from variations in time and temperature. The substrate hydrolysis was terminated with 1 M citrate buffer, pH 3.0, which reduced the environmental effects as compared to acetic acid. Overall a fourfold reduction in reagent consumption was achieved. A high correlation with clotting assays was obtained with various types of factor VIII concentrates as well as with plasma samples from blood donors and hemophilia A patients (r greater than 0.85). The accuracy was proven over the whole investigated range of factor VIII activities. Finally, the described microplate assay allows a high turnover of samples in a short period of time, still maintaining a coefficient of variation below 5%.

Contaminating fibrin in CPD-blood: solubility in plasma and distribution in blood components following separation

In order to estimate the solubility of contaminating fibrin in CPD-blood, thrombin induced fibrin polymerzation in CPD-plasma was examined by light scattering and fibrinopeptide A (FPA) determinations. In addition, I125 fibrin monomer enriched CPD-blood was used to investigate fibrin monomer retention in blood bags and transfusion filters (170 microns) and fibrin distribution in blood components derived from CPD-blood. Initial fibrin polymerization in CPD-blood occurred after conversion of 15 per cent of the fibrinogen to fibrin, implying that substantial amounts of fibrin may be kept solubilized in CPD-blood bags. Only minor amounts of I125 fibrin monomers were retained in blood bags (2.4 per cent) and in transfusion filters (2.9 per cent) after sham transfusions. After separating I125-fibrin monomer enriched CPD-blood into its constituent components, the major part of fibrin (75.0 per cent) could be traced in the cryoprecipitate.