Bronchoalveolar Lavage Galactomannan in Diagnosis of Invasive Pulmonary Aspergillosis among Solid-Organ Transplant Recipients

Abstract

We review the experience at our institution with galactomannan (GM) testing of bronchoalveolar lavage (BAL) fluid in the diagnosis of invasive pulmonary aspergillosis (IPA) among solid-organ transplant recipients. Among 81 patients for whom BAL GM testing was ordered (heart, 24; kidney, 22; liver, 19; lung, 16), there were five cases of proven or probable IPA. All five patients had BAL GM of >2.1 and survived following antifungal therapy. The sensitivity, specificity, and positive and negative predictive values for BAL GM testing at a cutoff of >1.0 were 100%, 90.8%, 41.7%, and 100%, respectively. The sensitivity of BAL GM testing was better than that of conventional tests such as serum GM or BAL cytology and culture. Moreover, a positive BAL GM test diagnosed IPA several days to 4 weeks before other methods for three patients. Twelve patients had BAL GM of >0.5 but no evidence of IPA. Among these, lung transplant recipients accounted for 41.7% (5/12) of the false-positive results, reflecting frequent colonization of airways in this population. Excluding lung transplants, the specificity and positive predictive value for other solid-organ transplants increased to 92.9% and 62.5%, respectively (cutoff, >1.0). In conclusion, BAL GM testing facilitated more-rapid diagnoses of IPA and the institution of antifungal therapy among non-lung solid-organ transplant recipients and helped to rule out IPA.

Comparison of Serum and Bronchoalveolar Lavage Galactomannan in Diagnosing Invasive Aspergillosis in Solid-Organ Transplant Recipients

“…5 Another study showed that among 81 patients with solid-organ transplant, the sensitivity and specificity of detecting galactomannan in bronchoalveolar lavage was 100% and 90% in diagnosing invasive aspergillosis (cutoff > 1). 8 False-positive cases are reported frequently, especially in patients with lung transplant, owing to a high rate of aspergillus colonization in these patients. 8 Another study of 116 lung transplant cases reported 60% sensitivity and 95% specificity for bronchoalveolar lavage galactomannan measuring (cutoff > 0.5).…”

“…8 False-positive cases are reported frequently, especially in patients with lung transplant, owing to a high rate of aspergillus colonization in these patients. 8 Another study of 116 lung transplant cases reported 60% sensitivity and 95% specificity for bronchoalveolar lavage galactomannan measuring (cutoff > 0.5). 7 In comparison, our study had a higher sensitivity and specificity with both methods (serum and bronchoalveolar lavage galactomannan measuring) in diagnosing invasive aspergillosis.…”

“…In the aforementioned studies, there were only 5 to 6 invasive aspergillosis cases. 7,8 In our study, we had 9 cases. However, our total sample size was small.…”

“…Therefore, rapid diagnosis and timely treatment may decrease mortality. 8 Routine diagnostic measures such as smear and culture for fungi, radiology, and clinical symptoms have low sensitivity and specificity. [9][10][11] Obtaining tissue samples is difficult owing to the condition of the patients as well as the risk of bleeding.…”

Antifungal stewardship considerations for adults and pediatrics

“…72 In contrast to the serum assay, BAL GM seems to perform well in SOT recipients. 73,74 There are no data to support the use of BDG testing in BAL. 69 Multiple causes of false-positive results for both BDG and GM have been reported, such as concomitant bacterial infections, b-lactam antibiotics, blood transfusions, blood-derived products, gluconate sodium-containing products, renal replacement therapy, and cross-reactivity with other fungi.…”