Infrared analysis of stored red blood cells

During storage under blood bank conditions, the characteristics of red blood cells must be monitored in order to assert a high quality of red cell concentrates (RCCs), destined for blood transfusion purposes. By means of infrared (FT-IR) spectroscopy, several characteristics can be measured simultaneously. ATR-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. 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 reduction in lipid packing density probably reflects the gradual change in cellular shape from discoidal to globular. By integration of selected absorption bands over a narrow range, storage time-dependent concentration changes in components of the glycolysis pathway could be estimated. Intracellular adenosine triphosphate (ATP) levels decrease during storage, but remain above the required 75% of the initial level after 35 days of storage. Glucose concentrations stay well above 5 mmol/L throughout the entire storage period.