Roy Chemaly, MD, from the University of Texas MD Anderson Cancer Center, Houston, TX, USA, provides an overview of a symposium on the role of immunodiagnostics for tuberculosis (TB) and cytomegalovirus (CMV) in hematopoietic cell transplant recipients held at the 2016 Annual Meeting of the European Society for Blood and Marrow Transplantation (EBMT) in Valencia, Spain. Prof. Chemaly describes how for around 100 years, there has only been one type of screening test for TB called the tuberculin skin test. However, immunocompromised patients and stem cell recipients do not react to the skin test. For the past 10 years, a blood test called interferon-gamma release assays (IGRAs) has been available. Prof. Chemaly discusses the T-SPOT.TB test in particular, which can screen patients for latent TB. The idea is to catch the infection early on, during the latent phase, in order to prevent progression. Prof. Chemaly also discusses the talk given by Prof. Hans Hirsch on the IGRA test, T-SPOT.CMV, which can predict the occurrence of CMV in stem cell transplant recipients. Prof. Chemaly describes how the T-spot test, which is a ELISPOT assay, works in detail.