Navigate Up
Sign In

The Process of Donating Blood

By far, the most common procedure that is carried out at the Donation Area is whole blood collection, as it is the one from which most products are obtained. The donor is greeted at the reception desk and a parking permit is issued. New donors are given a questionnaire to read beforehand in order to prepare themselves for the medical interview.
 
If the donor thinks that there is nothing in the questionnaire that prohibits him/her from donating blood, the donor is registered in the NBTS database. The donor is instructed to start drinking water at reception.
 
Following the registration, the donor is weighed, the haemoglobin (blood level) is checked and the body temperature is recorded.
 
Then, a doctor proceeds to interview the donor in a private interview room, by discussing the questionnaire and subsequently proceeds to carry out a brief medical examination. The questionnaire is discussed and explained in more detail. The donor might be deferred (not allowed to give blood) at this point.  Blood is a precious resource for which there is continoius demand.  When a donor is told to refrain from donating, it is either to protect the donor's health or that of the recipient.  Thus, it is very important that donors are honest during the medical interview and examination. There exists a high level of confidentiality and privacy in the medical examination as only authorised personnel have access to the medical history of the donors. 
 
On completing a successful interview and medical test, both donor and doctor sign the questionnaire after which the donor may proceed to donate blood. The donor is also signing acceptance that his/ her blood is being checked for blood group, Hep B, Hep C, HIV and Syphillis. Prior to signing, donors are informed that, in the case of true positive screening they will be permanently deferred from blood donation and they will be given appropriate advice and referred to specialists as appropriate.
 
Before one enters the donation area, the donor is offered water. A donor who has been without food for some hours is advised to have a light snack, like biscuits or sandwiches, before donating blood. This would prevent unwanted effects like dizziness during the blood donation procedure.
 
The donor proceeds to the donation area were s/he can lie comfortably on a couch, loosens any tight garments, like belts.  The nurse explains the procedure (especially to first time donors) and proceeds to performs skin disinfection at the venepuncture site. The actual donation should be finished within 5 to 10 minutes. Any strange sensations should be reported immediately to the nurse. The donor is also monitored for any abnormal gestures during donation or any signs of fainting.  When the blood donation is over, the donor is asked to press gently on the venepuncture site for some minutes.
 
 
After the donation, the donor is offered other refreshments and/or snacks. A brief assessment is carried out by the nurses to confirm that the donor is feeling well and after about 15 minutes the donor may leave. Female donors may donate again after 4 months, while male donors may donate after 3 months. 
 
What we end with after a donation
During a blood donation 475 mL of whole blood are drawn into the collection bag. This amounts to about one twelfth of the total blood volume in a 70 kg person. At the beginning of the blood donation some blood is collected in the sample pouch (which is attached to the kit) from which 3 sample bottles are filled. These sample bottles are to be used for screening of infectious disease markers and blood grouping tests and antibodies.
 
                

 
   
For confidentiality and traceability reasons all these samples are given a barcoded number, so that once the samples are transfered  to the Processing Laboratories, personnel cannot identify the donor. 
 
Blood Testing
All blood donations are tested for HIV 1 & 2, Hepatitis B, C, E, Syphilis, West Nile Virus.  These tests are carried out to ensure that the patient receives the safest possible blood product.
A blood grouping test for ABO and RhD is also carried out with each blood donation. This is to ensure the correct blood groups for the donor, as the ABO and RhD blood groups have the potential to cause severe haemolysis (break down of red cells in the recipient) and/ or haemolytic disease of the newborn (HDN). In HDN the mother produces antibodies after being exposed to an antigen she does not have. These antibodies then cross the placenta to break down the baby’s red cells. 
 
Some donations are also tested for cytomegalovirus (CMV) antibodies. This is done as some patients (but not all) require blood which is negative for CMV antibodies.
 
Blood Process at Blood Products
Freshly drawn whole blood maintains all its properties for a limited period of time.  After a whole blood donation, blood is separated into different components.  Whole blood is collected into the first bag of a 4-bag system.  At the Processing Laboratory, the rest of the bags in the bag system are used during separation of whole blood into the various components. 
 
The following photographs explain the process of blood seperation of a whole blood donation and how the other bags are used.
 
                                                                     
                                       Blood drawn from a donor.                  Whole blood donation.
 
                                                 
          Blood is being filtered.

                                                                                 
                                                    Blood is being ready for centrifugation.
 

                                                                            
 
                                                Seperation of blood after centrifugation.   
 
 
 
                                       
                              Blood products after seperation.               The 3 ending products.
 
     
Red cells are stored in a fridge between 20C to 60C for 42 days. Used for replacment in blood loss and for the therapy of anaemia.        
 
   
Plasma (Fresh Frozen) kept in freezers at temp of  -250C or lower for 36 months. My be used in coagulation disorders, thrombotic thrombocytopenic purpura (TTP). 
            
 Plateletes are stored in a special gas-permeable plastic bag at a temp of 200C to 240C on an agitator to guarantee availability of oxygen to platelets. These have to be used within 5 days, for patients who are unable to produce enough platelets, like patients with leukemia.