TMPRSS11D and systemic mastocytosis: An important aspect is that in HαT-positive cases with suspected or known SM, BST levels should be corrected for HαT.52,62,67 Although the optimal way of correction is still under debate, one suggested approach is to divide the tryptase value by 1 + the extra copy numbers of the alpha tryptase gene.62 In some individuals, this may lead to a reclassification from SM to CM (because of lack of a third minor SM criterion) or from smoldering SM to indolent systemic mastocytosis (because a B-finding is no longer demonstrable).