Cryopreservation of Rh negative blood for improved storage & utilisation by means of indigenous freezing bags & solutions & manual deglycerolisation.
OBJECTIVE
Cryopreservation allows donor blood to be stored for years, rather than weeks as in liquid storage. This is an established procedure in countries with a developed blood transfusion service. Cryopreservation has not been introduced in India, possibly because of the presumed high cost and complexity of the procedure. An attempt is made in this study, to cryopreserve Rh negative blood in a mechanical freezer using indigenous bags and solutions and manual deglycerolisation to reduce the cost of preservation.


METHODS
RBCs to be frozen were weighed and transferred by sterile welding to an 800 ml freezing bag. Based on RBC weight, 400-500 ml of glycerol (5.7 MpH 6.8) was added as cryopreservative. After extracellular and intracellular equilibration, excess glycerol was removed by centrifugation. Glycerolised RBCs were frozen at -80 degrees C in a mechanical freezer. Cryopreserved units were thawed at 37 degrees C and deglycerolised. Twenty one patients were transfused with the frozen deglycerolised RBCs after the usual pre-transfusion tests.


RESULTS
Haematocrit (Hct) values of the frozen deglycerolised units, complied with required standards, before addition of glycerol and post glycerolisation. RBC recovery was more than 80 per cent and Hct 83.3 per cent after deglycerolisation. Twenty one patients transfused with the frozen deglycerolised blood experienced no adverse effects and showed a 24 h mean post transfusion Hb increment of 0.73 g/dl.


CONCLUSIONS
Cryopreservation, unlike liquid storage, allows Rh negative blood of the required ABO groups to be stocked. Cryopreservation also improves its utilisation, reduces wastage and helps supplement the liquid stocks of Rh negative blood. The use of indigenous freezing bags and manual deglycerolisation has resulted in an inexpensive procedure, which can be integrated, with minor inputs, into any blood bank that is already preparing blood components.
Nanu
A
A
Department of Transfusion Medicine, All India Institute of Medical Sciences, New Delhi, India.
Lal
M
M
D000017:ABO Blood-Group System; D001793:Blood Preservation; D015925:Cryopreservation; D006801:Humans; D012204:Rh-Hr Blood-Group System
D000017:ABO Blood-Group System; D012204:Rh-Hr Blood-Group System