Transfusiology (Latin trans-, across + fundere, to pour, Greek logos-,word, thought) is part of clinical medicine which deals with transfusion of blood, its components and substitutes to achieve therapeutic effect through their actions on the composition of blood and fluids of the human body.
PRODUCTS USED FOR BLOOD TRANSFUSION
In clinical practice, whole blood, its components and products may be used.
Whole blood. Certain precautions are necessary in checking donor and blood for transfusion. No donor should be used who has a haemoglobin value below 12 g/l or who has a history of syphilis, malaria, viral hepatitis, chronic allergy, drug sensitivity or HIV infection. The donor's serologic test for syphilis and the test for antiHBsAg and HIV antibodies should be negative. Do Rh typing on both donor and recipient and check recipient's serum for unusual antigens. Cross-match blood. Blood for transfusion is drawn into containers with ACD (acid-citrate-dextrose), CDP (citrate-dextrose-phosphate), or CDPA-1 (citrate-dextrose-phosphate-adenine) anticoagulant (1:4), which binds calcium ions, prevents blood from coagulating and thus markedly prolongs the viability of red blood cells. Salts of EDTA and heparin may also be used as anticoagulants. Apart from the anticoagulant, the product contains antibiotics and glucose.
The blood must be stored at 4-6 °C. Properly stored blood may be used for transfusion until 21 days (with ACD) or 35 days (with CDPA) after withdrawal from the donor. Blood should not be used after the expire date.
It is noteworthy that not all the functions of the preserved blood are equally maintained. The most vulnerable are the haemostatic factors and immunity, whereas the oxygen-binding ability remains operable for a longer period. Therefore, when bleeding arrest is required, it is recommended that the blood be obtained at least 2-3 days prior to transfusion, and for the purpose of immune correction at least 5-7 days.