One hundred Egyptian beta-thalassaemic patients on a long-term transfusion/chelation programme were evaluated for the prevalence of all bladder sludge and stones and the associated risk factors. Fifty healthy individuals served as controls. Abdominal ultrasonography revealed that 14% of the thalassaemic patients had gall bladder sludge or stones [6% stones and 8% sludge]. The thalassaemic patients with this complication were older, had a higher prevalence of gall bladder symptoms, higher levels of pretransfusion haemoglobin, larger amounts of transfused red cells, and more were regularly transfused. Multiple logistic regression analysis revealed that the presence that gall bladder symptoms and the amount of transfused red cells were the only significant predictors of the occurrence of gall bladder sludge or stones.
Long-term storage of blood in liquid nitrogen, and the response of the recovered red cells to haemagglutination by viruses.