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Serum galactomannan-based early detection of invasive aspergillosis in hematology patients receiving effective anti-mold prophylaxis.
Clin Infect Dis. 2014 Aug 27;
Authors: Duarte RF, Sánchez-Ortega I, Cuesta I, Arnan M, Patiño B, Fernández de Sevilla A, Gudiol C, Ayats J, Cuenca-Estrella M
Abstract
BACKGROUND: There is a practical need to investigate the performance of the serum galactomannan (GM) assay in hematology patients with a potentially low pre-test risk of invasive aspergillosis following effective anti-mold prophylaxis.
METHODS: We present a four-year study with 262 unselected consecutive high-risk episodes, prospectively managed with posaconazole primary prophylaxis and a uniform diagnostic algorithm, including biweekly serum GM quantification for early detection of invasive aspergillosis.
RESULTS: 2972 serum GM tests were performed (median 11 per episode, 3-30); the vast majority was negative (96.7% tests; 83.6% episodes). The incidence of breakthrough invasive aspergillosis was 1.9% (5/262), all with true positive GM test results. Our study identified 30 false positive GM evaluable episodes (85.7%; 13.8% of all evaluable episodes), validating with real-life data the low positive predictive value of the assay in this setting (12%). In 26 out of these 30 episodes (86.7%), the false positive result/s occurred in tests performed as preemptive surveillance only. Conversely, in evaluable cases with positive GM tests and a clinical suspicion of invasive fungal disease, the performance of diagnostic-driven GM tests improved, with a positive predictive value of 89.6%.
CONCLUSIONS: The low pre-test risk of invasive aspergillosis in the context of effective anti-mold prophylaxis renders serum GM surveillance of asymptomatic patients unreliable, as all results would be either negative or false positive. The test remains useful to diagnose patients with a clinical suspicion of invasive fungal disease, calling for a more efficient co-positioning of effective prophylaxis and GM testing in this clinical setting.
PMID: 25165088 [PubMed - as supplied by publisher]