 A potential new target is gliotoxin GT, a secondary metabolite of several fungi, the most clinically important of which is Aspergillus2. GT is released during invasive growth, and can therefore be used as a biomarker of invasive fungal disease by GT-producing fungi. However, GT is quickly removed by red blood cells from circulation, making it an unreliable marker3. A degradation product of GT, bismethylthiogliotoxin bmGT, appears to be more stable as it is not taken up by red blood cells. Serum bmGT or bmGT in bronchoalveolar lavage BAL fluid has already been shown in small studies to be a potential marker of invasive aspergillosis, especially when used in combination with GM3-5. 