Most people breathe in Aspergillus spores on a daily basis without becoming unwell. However, in persons whose immune systems have been compromised by cancer treatment, bone marrow transplantation, or other immune-related condition, aspergillosis can quickly become invasive pulmonary aspergillosis (IPA or IA). This is the most severe type of aspergillosis, and it happens when the infection spreads quickly from the lungs to the brain, heart, kidneys, or skin. The most common cause of invasive pulmonary infection is A. fumigatus, followed by A. flavus and A. terreus. If left untreated, invasive aspergillosis can be lethal. ⁽¹⁾

Risk Factors for Invasive Pulmonary Aspergillosis
The most critical risk factor for IPA is neutropenia, particularly when the absolute neutrophil count is less than 500 cells/mm3. 

Transplantation of hematopoietic stem cells (HSCT) and solid-organ transplantation (particularly lung transplantation) are also significant risk factors. Several other features predispose transplant recipients to IPA: multiple immune defects, including prolonged neutropenia during the HSCT pre-engraftment phase; the use of anti-rejection or anti-graft versus host disease (GVHD) therapies (such as corticosteroids and cyclosporine); 
parenteral nutrition; multiple antibiotics; and prolonged hospitalization. ⁽²⁾

Recommendation for testing
The World Health Organization (WHO) Essential Diagnostics List is a list of recommended in vitro diagnostics that should be available at point-of-care and in laboratories in all countries to increase timely and life-saving diagnoses. 

Their latest 2021 edition included rapid tests for invasive and chronic aspergillosis. Together with P. jirovecii PCR, the tests endorsed as essential were Aspergillus antigen through Lateral Flow Device, critical for the diagnosis of IA, and Aspergillus antibody, critical for the diagnosis of chronic pulmonary aspergillosis which can mimic and complicate TB of the lungs. Both were included as new ‘essential diagnostics’ as they are far superior to culture in sensitivity and specificity. In addition to these, Aspergillus PCR for defining probable invasive pulmonary aspergillosis has been included in the 2020 guidelines from the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium (EORTC/MSG).

References

1. Jose Cadena, George R. Thompson, Thomas F. Patterson. Aspergillosis: Epidemiology, Diagnosis, and Treatment. Infectious Disease Clinics of North America, Volume 35, Issue 2, 2021. Pages 415-434, ISSN 0891-5520, ISBN 9780323812931. https://doi.org/10.1016/j.idc.2021.03.008.
2. M. Kousha, R. Tadi, A. O. Soubani. Pulmonary aspergillosis: a clinical review. European Respiratory Review Sep 2011, 20 (121) 156-174; DOI: 10.1183/09059180.00001011
3. Cornelia Lass-Flörl. How to make a fast diagnosis in invasive aspergillosis, Medical Mycology, Volume 57, Issue Supplement_2, April 2019, Pages S155 S160, https://doi.org/10.1093/mmy/myy103
4. Lewis W., et al. An evaluation of the performance of the IMMY sōna Aspergillus GM LFA when testing serum to aid in the diagnosis of IA. J Clin Micro. 2020; 00053-20.