The algorithm used both radiological and clinical evidence to exclude alternative diagnoses, such as infection, tumour progression, heart failure and pulmonary embolism, to arrive at a presumptive diagnosis of drug-associated ILD (Figure 2 ; Table 1) . Patients were categorised based on the strength of evidence supporting the diagnosis of drug-associated ILD (category 1, good supporting evidence for ILD; category 2, limited supporting evidence for ILD; category 3, no supporting evidence for ILD).