Infectious Disease Testing
To prevent transfusion transmission of blood borne infections, each unit of collected blood are routinely tested for Hepatitis B virus (HBV) surface antigen and nucleic acid, Hepatitis C Virus (HCV) antibodies and nucleic acid, Human Immuno-deficiency Virus (HIV) types I and II antibodies and antigen and HIV-1 nucleic acid, Hepatitis E Virus (HEV) nucleic acid, Human T-Lymphotropic Virus (HTLV) types I & II antibodies and Syphilis antibody. Blood component units that are tested negative for all these infectious markers and passed all other eligibility criteria can be labelled and are suitable for clinical transfusion. In addition, selected donations are tested for cytomegalovirus (CMV) antibodies for the purpose of providing CMV negative blood for clinically indicated patients.
Infectious disease screening includes:
- HIV Antigen, Antibodies and RNA
- Hepatitis B Virus Surface Antigen and DNA
- Hepatitis C Virus Antibodies and RNA
- Hepatitis E Virus RNA
- HTLV Antibodies
- Syphilis Antibodies
At present, the risk of transfusion transmitted infection cannot be entirely eliminated by testing technology that is currently available. Based on the observed epidemiology of infectious diseases in the local blood donor pool of 2016/17 and the window period of the infections, it is estimated that locally the residual risk of HIV infection in a blood product is approximately one in 3.4 million, hepatitis C is less than one in ten million and hepatitis B is about 1 in 126,000. It is not feasible to generalise the precise risk of every infection for any patients receiving blood transfusion as there are other variable factors that would affect the risk estimation, such as the immune / infection status of the patient, the type and the quantity of blood components transfused, etc.