The Value of Galactomannan Test in the Evaluation of Invasive Aspergillosis in Patients with Prolonged Febrile Neutropenia

Introduction: Early treatment and prognosis of galactomannan antijenemia is essential in patients with high risk of invasive aspergillosis. This prospective observational study was done to evaluate the effect of galactomannan antigen test on diagnosis and antifungal treatment of febrile neutropenic patients who are still having fever despite wide spectrum antibiotic treatment. Materials and Methods: One hundred and twenty six febrile neutropenic attacks belonging to 109 cases between January 2009 and August 2010 were included to the study. The patients were mostly with hematologic malignancy, and galactomannan tested because of having fever more than five days despite wide spectrum antibiotic treatment. Cases with another fungal infection diagnosis were not included. All cases were evaluated with high resolution computer tomography parallel to galactomannan antigen test. Results: Sixty three (50%) patients were diagnosed with abnormal finding according to high resolution computer tomography, whereas 57 (45%) were galactomannan positive. One proved, two high probabilistic, four probabilistic, totally 7 (6%) cases were diagnosed as invasive aspergillosis according to EORTC/MSG criteria. Galactomannan sensitivitity was low (43%) but negative predictive value was found high (94%). Specificity increased as galactomannan optic density index limit increased. In galactomannan positive cases, neutropenia level (p= 0.001) and antifungal startup ratio were high (p= 0.007), and antifungal treatment period (p= 0.003) were longer. There was no meaningful relation between galactomannan positivity and abnormal finding at high resolution computer tomography for diagnosis (p= 0.371). “Preemptive“ antifungal treatment was started to 63 (50%) of cases, who are prospective candidates for "empiric” antifungal treatment. Conclusion: Although solitary serum galactomannan level sensitivity for invasive aspergillosis diagnosis is low, it has importance as negative predictive value may be high. “Preemptive” treatment based on galactomannan test has decreased antifungal usage to a crucial degree. However, with the evaluation of galactomannan test on more proved invasive aspergillosis cases “preemptive” antifungal description would be made exactly and galactomannan test would be more respected.