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.