A 2-year Review of the Diagnostic Performance of Serum and Bronchoalveolar Lavage Galactomannan Testing in Lung Transplant Recipients in a National Heart and Lung Transplant Centre

Background: The 2015 International Society for Heart and Lung Transplant (ISHLT) fungal guidelines recommend the use of bronchoalveolar lavage (BAL) galactomannan over serum galactomannan for the diagnosis of invasive aspergillosis (IA) in lung transplant (LTx) recipients, based on limited evidence. Galactomannan testing is costly.

Methods: A single-center, retrospective cohort study reviewing all 814 serum and BAL galactomannan samples received from 184 LTx recipients in our center between 2021 and 2022 and assessing their diagnostic performance in the diagnosis of IA.

Results: Over the study period, 394 serum galactomannan samples were received from 144 patients and 420 BAL galactomannan samples from 143 patients. Using a cut-off of ≥ 1.0 for BAL galactomannan, the sensitivity and specificity were 65.9% and 98.4%, respectively. In total, 30 patients had positive BAL galactomannan. Antifungal therapy was commenced or continued in 29 of these patients either as targeted or pre-emptive treatment. Using a cut-off of ≥ 0.5 for serum galactomannan, the sensitivity and specificity were 9.7% and 99.7%, respectively. In total, four patients had a positive serum galactomannan. All four patients were either already on antifungal treatment for IA or were started before the serum galactomannan result was available, supported by laboratory, clinical, and radiological findings. A positive serum galactomannan was used to monitor treatment response in one patient.

Conclusion: Serum galactomannan is not a valuable test in the diagnosis of IA in our LTx recipients, is costly, and does not remove the need for bronchoscopy and BAL galactomannan. This supports the ISHLT recommendation.