Allogeneic hematopoietic stem cell transplantation (HSCT) is a valuable treatment option for patients with some blood/malignant disorders. However, this procedure may be complicated by life-threatening infections, including invasive aspergillosis (IA). Diagnosis of IA is challenging due to nonspecific symptoms that present similar to other infections; and delays in initiation of treatment are associated with poor outcomes. The galactomannan assay (GM) is a widely used test for the early diagnosis of IA and allows for prompt initiation of antifungal therapy. However, a positive (+) GM result requires further workup for a definitive diagnosis. Furthermore, false positives can lead to unnecessary treatment with expensive and potentially toxic antifungal medications. At UC San Diego Health, allogeneic HSCT patients not on mold-active agents for antifungal prophylaxis have GM tested weekly until 100 days post-HSCT. This study aims to describe the utility of routine GM assays in this HSCT population.
This is a retrospective single-center study of patients > 18 years of age post-allogeneic HSCT at UC San Diego Health from January 2015 - December 2016 with GM results reported in the electronic medical record. Data includes patient demographics, GM results up to 100 days post-HSCT, antifungal prophylaxis, further testing performed, diagnosis of possible, probable and proven IA, and outcome of infection.
In total, 108 patients met criteria for enrollment in this study. There were a total of 1354 GM results, of which only 2.8% (38) were positive (> = 1 +GM) in 25 patients (23% of all patients). Of these, 20 of 25 (80%) were found to be false positives. In total, 7 of 108 patients had a diagnosis of possible or probable IA. Of the seven, 2 had 0 +GM, and 2 had 1 +GM. In the 2 with 1+GM, IA diagnosis was notably made prior to the +GM result. In only 3 of the 7 cases did +GM screening lead to diagnosis of IA; of these, 2 patients had acute GVHD and 1 developed infection during neutropenia, in the first 2 weeks post-HSCT.
Routine GM testing adds to cost and is not a useful predictor of IA infection in the studied population. Studies to determine what populations, if any, would most benefit from routine pre-emptive GM or other fungal screening are needed.
N. Haste, None
R. Taplitz, U.C.S.D.: Scientific Advisor , Consulting fee .