Interlaboratory comparison of red-cell ATP, 2,3-diphosphoglycerate and haemolysis measurements

NonFreezable Preservation of Human Red Blood Cells at -8 °C

Red blood cell (RBC) preservation is very important in human health. The RBCs are usually preserved at 4 ± 2 °C without freezing or at a very low temperature (-80 °C or liquid nitrogen) with deep freezing. Herein, non freezable preservation of RBCs at a subzero temperature is reported to prolong the preservation time compared with that at 4 ± 2 °C. By adding glycerol and poly(ethylene glycol) (PEG) (average number molecular weight 400, PEG-400) into the preservation solution, the freezing point is decreased and the hemolysis is kept low. The cell metabolism of stored RBCs at -8 °C is reduced, and the shelf life of RBCs extends up to at least 70 days. At the end of preservation, the pH decreases a little bit to demonstrate the low metabolic rate of RBCs stored at subzero temperatures. After quick washing, the RBC survival rate is ca. 95%. The adenosine triphosphate, 2,3-diphosphoglycerate, and cell deformation ability of the washed RBCs are maintained at a high level, while the malondialdehyde is relatively low, which verifies the high quality of RBCs stored at this condition.

Acute Cycling Exercise Induces Changes in Red Blood Cell Deformability and Membrane Lipid Remodeling

Here we describe the effects of a controlled, 30 min, high-intensity cycling test on blood rheology and the metabolic profiles of red blood cells (RBCs) and plasma from well-trained males. RBCs demonstrated decreased deformability and trended toward increased generation of microparticles after the test. Meanwhile, metabolomics and lipidomics highlighted oxidative stress and activation of membrane lipid remodeling mechanisms in order to cope with altered properties of circulation resulting from physical exertion during the cycling test. Of note, intermediates from coenzyme A (CoA) synthesis for conjugation to fatty acyl chains, in parallel with reversible conversion of carnitine and acylcarnitines, emerged as metabolites that significantly correlate with RBC deformability and the generation of microparticles during exercise. Taken together, we propose that RBC membrane remodeling and repair plays an active role in the physiologic response to exercise by altering RBC properties.

Feasibility of photoacoustic imaging for the non-invasive quality management of stored blood bags

BACKGROUND AND OBJECTIVES

During the in vitro storage of red blood cells (RBCs), unfavourable changes (storage lesions) cause a rapid consumption of intracellular diphosphoglycerate. The latter deregulates the oxygen-haemoglobin binding potential, subsequently increasing oxygen saturation (SO₂ ) and membrane degradation, transforming RBCs from biconcave discs to rigid spherical bodies (spheroechinocytes). Current laboratory techniques invasively extract RBC samples to assess the quality of red cell concentrate (RCC) units. Optical technologies could provide a means of assessing quality non-invasively.

MATERIALS AND METHODS

A photoacoustic (PA) imaging technique was developed for acquiring the SO₂ of blood bags non-invasively. Seven RCC units were monitored every 3-5 days until expiry (6 weeks). Measurements were validated against a conventional blood gas analyzer (BGA). Using an image flow cytometry assay, morphological profile trends were compared against the SO₂ trends during blood bag storage.

RESULTS

A strong correlation (r²  ≥ 0·95) was found when comparing temporal data between PA and BGA SO₂ measurements. Inter-sample PA variability was found to be similar to that produced by BGA (±0·8%). A strong correlation was found to exist between the temporal changes in SO₂ and relative spheroechinocyte population (0·79 ≤ r²  ≤ 0·97).

CONCLUSION

This study suggests that PA imaging can non-invasively track the SO₂ of stored RBCs non-invasively. By longitudinally monitoring the change in SO₂ , it is possible to infer the effects of the storage lesion on RBC morphology. This non-invasive monitoring technique allows for the assessment of blood bags, without compromising sterility pre-transfusion.

Impact of technical and assay variation on reporting of hemolysis in stored red blood cell products

BACKGROUND

Hemolysis of RBCs is an important measure of product quality and is influenced by donor factors, blood component manufacturing and storage. Percent hemolysis is determined using hematocrit (Hct), supernatant Hb (SHb) and total Hb (THb), each of which can be measured using a variety of methods.

METHODS

Sixteen members of an international collaborative were surveyed to understand equipment and procedural variation in hemolysis testing. In a laboratory-based evaluation, we examined how hemolysis was impacted by: measurement of Hct, SHb, THb and number and force of centrifugations for SHb preparation. The number and size of extracellular vesicles (EVs) was also examined.

RESULTS

There was no consensus in equipment or procedures used by international laboratories to measure hemolysis. The centrifugation force used to prepare samples influenced SHb concentration when a single or double (p=0.0001) centrifugation step was used. The number and force of centrifugation related directly to the ability to remove EVs and EV-bound Hb from samples. Hemolysis varied significantly from 0.16% to 0.32% (mean of 0.22%) depending on the combination of methods or centrifugation conditions used to test expired samples.

CONCLUSION

Method and preparative procedures have a critical impact on measurement of hemolysis in RCC.

The effect of processing method on the in vitro characteristics of red blood cell products

BACKGROUND AND OBJECTIVES

While the clinical impact of differences in red blood cell (RBC) component processing methods is unknown, there are concerns they may be confounding variables in studies such as the ongoing 'age of blood' investigations. Here, we compare the in vitro characteristics of red cell concentrates (RCCs) produced by several different processing methods.

MATERIALS AND METHODS

Nine processing methods were examined: three apheresis methods (Alyx, MCS+ and Trima), as well as leucoreduced whole blood-derived RCCs produced by buffy coat and whole blood filtration and non-leucoreduced RCCs. RCCs were stored in saline-adenine-glucose-mannitol or additive solutions (AS) 1 or 3 for 42 days, with quality tested on day 5 and day 42.

RESULTS

Many significant product differences were observed both early in and at the end of storage. Mean haemoglobin (Hb) ranged from 52 to 71 g/unit and mean Hct from 59·5 to 64·8%. Most RCC passed regulated quality control criteria according to Canadian Standards Association guidelines, although there were some failures relating to Hb content and residual WBC counts.

CONCLUSION

Processing method impacts RCC characteristics throughout storage; better understanding of these differences and reporting of processing method details is critical.

Measures of stored red blood cell quality

Blood banking underpins modern medical care, but blood storage, necessary for testing and inventory management, reduces the safety and efficacy of individual units of red blood cells (RBCs). Stored RBCs are damaged by the accumulation of their own waste products, by enzymatic and oxidative injury, and by metabolically programmed cell death. These chemical activities lead to a complex RBC storage lesion that includes haemolysis, reduced in vivo recovery, energy and membrane loss, altered oxygen release, reduced adenosine tri-phosphate and nitric oxide secretion, and shedding of toxic products. These toxic products include lysophospholipids that can cause transfusion-related acute lung injury, free iron that can potentiate infections and cause inflammation, and shed microvesicles that can scavenge nitric oxide and potentiate inflammation and thrombosis. However, most of the obvious negative outcomes of RBC storage are uncommon and appear to be related to exceptionally bad units. Generally, the quality of stored RBCs is highly related to the conditions of storage, so refrigerator temperature, intact bags, residual leucocyte counts and visible haemolysis remain excellent general measures. Specific biochemical measures, such as adenosine 5'-triphosphate (ATP) and 2,3-diphosphoglycerate (DPG) concentrations, calcium and potassium content or lipid breakdown products, require specialized measures that are not widely available, involve destructive testing and generally reflect only a part of the storage lesion. This review describes a number of components of the storage lesion and their measurement and attempts to access the utility of the measures.

In vitro parameters of cryopreserved leucodepleted and non-leucodepleted red blood cells collected by apheresis or from whole blood and stored in AS-3 for 21 days after thawing

BACKGROUND

The aim of the study was to evaluate the in vitro quality of cryopreserved red blood cells obtained from different sources with or without leucodepletion and stored at 4±2 °C in AS-3 for up to 21 days.

MATERIALS AND METHODS

Red blood cells were collected by four methods: double erythrocytapheresis, whole blood collection with buffy coat removal, double erythrocytapheresis with in-line leucofiltration, or whole blood collection with in-line leucofiltration. All four types of red blood cells were frozen in 40% glycerol after collection and stored at a temperature below -65 °C for at least 30 days, thawed, deglycerolised and subsequently reconstituted in AS-3. The in vitro haematological and biochemical properties of the thawed red blood cells were tested on days 0, 7, 14, and 21 after deglycerolisation and reconstitution.

RESULTS

Overall, 72 units were processed. Leucodepletion of cryopreserved red blood cells units reduced haemolysis, lowered ammonia concentration, preserved pH and osmolality and led to sustained higher concentrations of ATP. In contrast, the source of red blood cells (apheresis or whole blood) did not affect their quality.

DISCUSSION

The quality of all investigated red blood cells units was the same as or even better than that of erythrocytes obtained from double erythrocytapheresis with a 24-hour survival of at least 86% after up to 3 weeks of storage in AS-3.

Scientific problems in the regulation of red blood cell products

BACKGROUND

For the past 30 years, red blood cell (RBC) storage systems have been licensed in the United States based on the demonstration that 24-hour in vivo recovery was greater than 75% and hemolysis was less than 1%. Now additional requirements for storage system licensure have being added. The meaning and value of these new requirements have been questioned.

STUDY DESIGN AND METHODS

The literature regarding the performance of present and suggested new tests for RBC licensure was reviewed.

RESULTS

(51) Cr 24-hr in vivo recovery has an intrinsic 4% error of measurement whereas the error in measures of hemolysis is less than 0.1%. Both measures have large donor-dependent end-of-storage variability; nevertheless, they have successfully guided RBC storage system development for six decades. Adenosine 5'-triphosphate and 2,3-diphosphoglycerate are difficult to measure accurately and international shared-sample studies suggest 6 and 11% coefficients of variation across laboratories. There is no readily available way to measure the oxygen equilibrium curve accurately. The new failure criteria provide no useful information and randomly fail good products.

CONCLUSIONS

Attempts to expand the useful regulatory requirements for RBC storage system licensure are limited by poor understanding of the storage lesion and its effect of RBC performance. Measures of (51) Cr 24-hour in vivo recovery remain critical and resources for this measure are limiting. The interaction between limited testing resources and large donor variability remains a major limit on RBC storage system development. It is important that new required tests contribute meaningful information and not make development and licensure of better products more difficult.

Improving the predictive value of red blood cell storage trials: lessons from the Biomedical Excellence for Safer Transfusion (BEST) Collaborative Trial 41

BACKGROUND

Storage system trials are conducted for the development and licensure of new red blood cell (RBC) storage systems or to validate new ways of using existing systems. Results from one laboratory are often difficult to reproduce in another laboratory, leading to confusion.

STUDY DESIGN AND METHODS

A large international trial was designed to test the warm overnight hold using common donor collection systems and pooling of units to reduce interlaboratory variability of measures of RBC storage. Methods of measurement were left to the individual laboratories. pH was measured on both laboratory pH meters and clinical blood gas machines. Adenosine 5'-monophosphate (ATP) was measured by a variety of methods.

RESULTS

Intralaboratory variability of measures of pH and ATP were small compared to interlaboratory variability. Initial pH measures between laboratories varied over 0.4 pH units, while RBC ATP concentrations varied 2 to 10 µMol/g hemoglobin. pH variability was partly related to temperature of measurement, but the variability in ATP measures was a problem of both methods and standards.

CONCLUSIONS

Common methods and shared standards between laboratories would improve the interpretation of RBC storage measurements. Improved comparability between major laboratories would speed the development of better RBC storage systems.

Red blood cell hemolysis during blood bank storage: using national quality management data to answer basic scientific questions

BACKGROUND

Hemolysis of red blood cells (RBCs) during blood bank storage is the most obvious manifestation of RBC storage system failure. However, its analysis is made difficult because the largest source of interunit difference is donor specific. Availability of data from national blood systems on large numbers of RBC units used for internal quality control (QC) purposes and stored and processed in uniform ways permits statistical analysis.

STUDY DESIGN AND METHODS

Measures of hemolysis during and at the end of storage on randomly selected donor units observed for QC purposes were obtained from four national blood systems. Groups of these measures from units that had undergone similar processing and storage were sorted to create histograms and the histograms were compared statistically.

RESULTS

A total of 14,087 measures were obtained under seven storage conditions, including more than 12,000 measures made in a single country under four closely related conditions. Distributions of percent hemolysis are skewed normal and outliers are random. Additive solutions appear to be equivalent, except that the 42 mmol/L mannitol in AS-1 reduces hemolysis compared to conventional 30 mmol/L mannitol in saline, adenine, glucose, and mannitol. Increasing storage from 35 to 42 days increased measured hemolysis by 30% and leukoreduction decreased it by 53%.

CONCLUSIONS

Large national data sets provide useful information about the distribution of hemolysis at the end of RBC storage. This information can aid blood storage system development and regulatory science.

A single assay for multiple storage-sensitive red blood cell characteristics by means of infrared spectroscopy

BACKGROUND

To maintain a high quality of red blood cells (RBCs), RBC characteristics must be followed during storage under blood bank conditions. By means of infrared (IR) spectroscopy, several characteristics can be measured simultaneously.

STUDY DESIGN AND METHODS

IR spectra were acquired for samples from RBCs that were collected and stored according to Dutch blood bank procedures for a period of up to 50 days. Spectra of the soluble cell components were acquired separately after hypotonic lysis of the cells, followed by centrifugation. Characteristic vibrational bands were analyzed with respect to storage time-dependent changes in peak position and in intensity.

RESULTS

A decrease in corresponding peak intensities indicates that RBCs lose protein and lipid during storage. Changes in protein secondary structure during storage are largely confined to integral membrane proteins and membrane-associated proteins. A concurrent decrease in lipid packing density probably reflects the gradual change in cellular shape from discoidal to globular. By integration over a narrow range, storage-dependent changes in intracellular adenosine triphosphate (ATP) and glucose levels could be estimated. ATP levels decrease during storage, but stay above the required 75% of the initial level after 35 days of storage. Glucose concentrations stay well above 5 mmol/L over the entire storage period.

CONCLUSION

IR spectroscopy is a promising technique to follow structural and metabolic changes in RBCs during storage under blood bank conditions. Several variables can be determined rapidly in a single measurement.

A comparative study of common techniques used to measure haemolysis in stored red cell concentrates

BACKGROUND AND OBJECTIVES

There is no standardized method of measuring the parameters for haemolysis determination of red cell concentrate (RCC). Three haemoglobin quantification methods (automated analyser, Harboe and Drabkin's) and two methods of haematocrit measurement (automated analyser and microcapillary centrifugation) were evaluated for use with RCC.

MATERIALS AND METHODS

Twenty stored RCC were assayed for total haemoglobin, supernatant haemoglobin and haematocrit.

RESULTS

Drabkin's and Harboe methods were linear (r(2) > or = 0.995) over 0.015-220 g/l haemoglobin. Overestimation by Drabkin's increased from 0% at 220 g/l to 137% at 0.015 g/l haemoglobin. Harboe values generally stayed within 6% of expected while haematology analyser values had a maximum 11% underestimation above 10 g/l. Analyser total haemoglobin was significantly lower (202 +/- 22 g/l) than Drabkin's (224 +/- 24 g/l) and Harboe (222 +/- 22 g/l) values. Haematocrit was greater via the analyser (65.7 +/- 5.7%) than with microcapillary centrifugation (59.3 +/- 5.7%).

CONCLUSIONS

Harboe and Drabkin's methods are suitable for measuring total haemoglobin and supernatant haemoglobin in RCC. The analyser gave higher haematocrit values (11% on average) than did microcapillary centrifugation.

Overnight storage of whole blood: a comparison of two designs of butane-1,4-diol cooling plates

BACKGROUND

Whole blood (WB) can be stored overnight before processing, provided that it is quickly cooled to room temperature (20-25 degrees C), for example, with butane-1,4-diol plates. A new design of cooling plates became available (CompoCool-WB, Fresenius HemoCare), where WB must be placed vertically against the plates, versus placing of WB under plates in the current version (Compocool). This study compared cooling efficiency and in vitro quality of plasma and of stored white cell (WBC)-reduced red cells (RBCs) from overnight-stored WB, cooled with either of the systems.

STUDY DESIGN AND METHODS

Temperature curves following cooling with Compocool or CompoCool-WB were studied with a 25 percent glycerol solution as simulated WB. WB from voluntary donors was cooled with Compocool or CompoCool-WB, stored overnight at room temperature, centrifuged, and separated into components. WBC-reduced RBCs in SAGM were stored until Day 42 with measurement of in vitro parameters (n=23/group).

RESULTS

Simulated WB reached a temperature of less than 25 degrees C after 2:15+/-1:04 hours for Compocool versus 1:39+/-0:38 hours for CompoCool-WB (p=0.02). On Day 35, RBCs had a hemolysis of 0.3+/-0.2 percent in both groups, and ATP levels were 3.3+/-0.5 and 3.6+/-0.5 micromol per g hemoglobin for Compocool and CompoCool-WB, respectively (not significant). Factor VIII content in plasma was 1.05+/-0.25 and 0.97+/-0.18 IU per mL for Compocool and CompoCool-WB, respectively.

CONCLUSION

WB can be cooled to room temperature within 2 hours with both Compocool and CompoCool-WB butane-1,4-diol plates, improving temperature uniformity in WB donations. Application of either design for overnight storage of WB at room temperature had no adverse effects on the composition of subsequently prepared blood components.

Evolution of adverse changes in stored RBCs

Recent studies have underscored questions about the balance of risk and benefit of RBC transfusion. A better understanding of the nature and timing of molecular and functional changes in stored RBCs may provide strategies to improve the balance of benefit and risk of RBC transfusion. We analyzed changes occurring during RBC storage focusing on RBC deformability, RBC-dependent vasoregulatory function, and S-nitrosohemoglobin (SNO-Hb), through which hemoglobin (Hb) O(2) desaturation is coupled to regional increases in blood flow in vivo (hypoxic vasodilation). Five hundred ml of blood from each of 15 healthy volunteers was processed into leukofiltered, additive solution 3-exposed RBCs and stored at 1-6 degrees C according to AABB standards. Blood was subjected to 26 assays at 0, 3, 8, 24 and 96 h, and at 1, 2, 3, 4, and 6 weeks. RBC SNO-Hb decreased rapidly (1.2 x 10(-4) at 3 h vs. 6.5 x 10(-4) (fresh) mol S-nitrosothiol (SNO)/mol Hb tetramer (P = 0.032, mercuric-displaced photolysis-chemiluminescence assay), and remained low over the 42-day period. The decline was corroborated by using the carbon monoxide-saturated copper-cysteine assay [3.0 x 10(-5) at 3 h vs. 9.0 x 10(-5) (fresh) mol SNO/mol Hb]. In parallel, vasodilation by stored RBCs was significantly depressed. RBC deformability assayed at a physiological shear stress decreased gradually over the 42-day period (P < 0.001). Time courses vary for several storage-induced defects that might account for recent observations linking blood transfusion with adverse outcomes. Of clinical concern is that SNO levels, and their physiological correlate, RBC-dependent vasodilation, become depressed soon after collection, suggesting that even "fresh" blood may have developed adverse biological characteristics.

Automated collection of double red blood cell units with a variable-volume separation chamber

BACKGROUND

Automated collection of blood components offers multiple advantages and has prompted development of portable devices. This study sought to document the biochemical and hematologic properties and in vivo recovery of red cells (RBCs) collected via a new device that employed a variable-volume centrifugal separation chamber.

STUDY DESIGN AND METHODS

Normal subjects (n = 153) donated 2 units of RBCs via an automated blood collection system (Cymbal, Haemonetics). Procedures were conducted with wall outlet power (n = 49) or the device's battery source (n = 104). Units were collected with or without leukoreduction filtration and were stored in AS-3 for 42 days. The units were assessed via standard biochemical and hematologic tests before and after storage, and 24 leukoreduced (LR) and 24 non-LR RBCs were radiolabeled on Day 42 with Na(2)(51)CrO(4) for autologous return to determine recovery at 24 hours with concomitant determination of RBC volume via infusion of (99m)Tc-labeled fresh RBCs.

RESULTS

Two standard RBC units (targeted to contain 180 mL of RBCs plus 100 mL of AS-3) could be collected in 35.7 +/- 2.0 minutes (n = 30) or 40.3 +/- 2.7 minutes for LR RBCs (n = 92). An additional 31 collections were conducted successfully with intentional filter bypassing. RBC units contained 104 +/- 4.1 percent of their targeted volumes (170-204 mL of RBCs), and LR RBCs contained 92 percent of non-LR RBCs' hemoglobin. All LR RBCs contained less than 1 x 10(6) white blood cells. Mean hemolysis was below 0.8 percent (Day 42) for all configurations. Adenosine triphosphate was well preserved. Mean recovery was 82 +/- 4.9 percent for RBCs and 84 +/- 7.0 percent for LR RBCs.

CONCLUSIONS

The Cymbal device provided quick and efficient collection of 2 RBC units with properties meeting regulatory requirements and consistent with good clinical utility.

Effects of erythrocyte flexibility on microvascular perfusion and oxygenation during acute anemia

Responses to exchange transfusion using red blood cells (RBCs) with normal and reduced flexibility were studied in the hamster window chamber model during acute moderate isovolemic hemodilution to determine the role of RBC membrane stiffness in microvascular perfusion and tissue oxygenation. Erythrocyte stiffness was increased by 30-min incubation in 0.02% glutaraldehyde solution, and unreacted glutaraldehyde was completely removed. Filtration pressure through 5-μm pore size filters was used to quantify stiffness of the RBCs. Anemic conditions were induced by two isovolemic hemodilution steps using 6% 70-kDa dextran to a hematocrit (Hct) of 18% (moderate hemodilution). The protocol continued with an exchange transfusion to reduce native RBCs to 75% of baseline (11% Hct) with either fresh RBCs (RBC group) or reduced-flexibility RBCs (GRBC group) suspended in 5% albumin at 18% Hct; a plasma expander (6% 70-kDa dextran; Dex70 group) was used as control. Systemic parameters, microvascular perfusion, capillary perfusion [functional capillary density (FCD)], and oxygen levels across the microvascular network were measured by noninvasive methods. RBC deformability for GRBCs was significantly decreased compared with RBCs and moderate hemodilution conditions. The GRBC group had a greater mean arterial blood pressure (MAP) than the RBC and Dex70 groups. FCD was substantially higher for RBC (0.81 ± 0.07 of baseline) vs. GRBC (0.32 ± 0.10 of baseline) and Dex70 (0.38 ± 0.10 of baseline) groups. Microvascular tissue Po2 was significantly lower for Dex70 and GRBC vs. RBC groups and the moderate hemodilution condition. Results were attributed to decreased oxygen uploading in the lungs and obstruction of tissue capillaries by rigidified RBCs, indicating that the effects impairing RBC flexibility are magnified at the microvascular level, where perfusion and oxygenation may define transfusion outcome.

The effect of plastic overwraps on storage measures of red cell concentrates

BACKGROUND

For hygienic purposes, plastic overwraps can be used for storage of leucoreduced red cell concentrates (LR-RCC). However, the effect of the use of such overwrapping on in vitro parameters during 42 days of storage was unknown.

METHODS

In paired experiments, LR-RCCs in SAGM (saline, adenine, glucose, mannitol) were packed in two types of polyethylene overwrap or in a polypropylene overwrap; no overwrap served as reference (n = 12 paired experiments). Units were stored at 2-6 degrees C for 42 days and sampled at regular intervals for in vitro analysis.

RESULTS

No significant effect was found for any of the overwraps investigated. All units contained > 2.7 micromol adenosine triphosphate per gram haemoglobin and had a haemolysis rate well below 0.8% on Day 42.

CONCLUSION

The use of plastic overwraps does not affect red cell quality markers in vitro.

In-vitro evaluation of the PALL Leukotrap Affinity Prion Reduction Filter as a secondary device following primary leucoreduction

BACKGROUND AND OBJECTIVES

A filter (PRF1) designed to remove abnormal prion proteins from red-cell units has been developed. The purpose of this study was to evaluate the quality of red cells produced using this device.

MATERIALS AND METHODS

Leucocyte-depleted red-cell units (CPD, CPD-A1 and CPD/SAGM) processed according to standard UK practices were filtered using PRF1. Filtered and control units were stored and sampled on day 1, day 7 and on the date of expiry and were tested using standard measures of red-cell quality.

RESULTS

Filtered units were found to have significantly higher percentage haemolysis levels, lower haemoglobin levels and a smaller volume compared with controls. All results, however, were well within the permitted 0.8% haemolysis level at the end of storage and all units met the UK guidelines for haemoglobin and volume. The other test parameters measured showed no significant differences between the test and control units.

CONCLUSIONS

The PRF1 filter was found to be easy to use and resulted in red-cell units that met all relevant UK and European Guidelines.