“…Recent studies identifying and quantitating the KIT D816V mutation in peripheral blood (PB) in adults have suggested it to be a valuable tool for diagnosis, (Kristensen et al, 2011(Kristensen et al, , 2014Jara-Acevedo et al, 2015) to determine disease burden and monitoring (Erben et al, 2014), and to assess response to therapy (Hoermann et al, 2014). In adults, the KIT D816V allelic burden in PB correlates with serum tryptase (Kristensen et al, 2013;Erben et al, 2014;Hoermann et al, 2014). However, the diagnosis of systemic disease in children remains a challenge because, outside of the clinical finding of organomegaly, which correlates with systemic disease, surrogate markers to help identify those children where a marrow examination might be warranted to establish systemic disease, are lacking (Carter et al, 2015).…”