14th June each year is the World Health Organization (WHO) world blood donor day. Blood donation is essential to save the lives and/or improve the health of many patients. Dr John Frater is a MRC Senior Clinical Fellow in the Experimental Medicine Division and a practicing clinician in acute medicine. His main research interest is trying to eradicate HIV. NDM spoke to Dr Frater about the importance of blood donation and why in the UK we screen all donated blood for diseases such as HIV.