Before starting immunosuppressive therapy, it is important to screen for latent tuberculosis and, in case of particular exposures (e.g. travel, origin,…), for parasitosis such as amoebiasis, echinococcosis, strongyloidiasis and American trypanosomiasis. The Division of Tropical and Humanitarian Medicine of the Geneva University Hospitals has developed an algorithm to identify which screening is recommended according to exposure. Analysis of this practice shows that the most frequently detected latent disease is tuberculosis, followed by strongyloidiasis. For the latter, as the sensitivity of the serological test is reduced due to immunosuppression, the algorithm combine antibody testing with parasitological (Baermann and culture) and molecular (PCR) stool testing.