Table 3.

Stepwise Approach to Diagnosis and Management of CAPA

Step	Objectives	Comments
Understand local epidemiology of CAPA and aspergillosis	Use retrospective reviews and pathology/autopsy data to get rough estimate of burdens at your hospital	Pilot data for CAPA incidence locally may be useful. Historic incidence of aspergillosis in vulnerable populations (eg, transplant) and ICUs may give sense of relative local burdens
2.Define at-risk patient populations for CAPA	Use local data and review of published literature to define risk factors relevant at your hospital	Test performance, PPVs and NPVs will be most useful if testing is directed toward populations with reasonable pretest likelihoods of aspergillosis, rather than including all patients with COVID-19
3.Estimate PPVs and NPVs given approximate pretest likelihoods	Use data from steps 1 and 2 to calculate estimated PPVs and NPVs (Table 1)	Even if exact numbers are not available, it may be possible to approximate PPVs and NPVs for aspergillosis within ranges, and classify these as relatively low, medium, or high
4.Develop strategies to direct testing to at-risk populations	Engage clinical services relevant to at-risk patients to develop testing, interpretive and management protocols	Many services are involved in care of critically ill patients with COVID-19. Engagement with and buy-in from services will improve compliance with protocols and treatment recommendations. Directed testing rather than routine surveillance testing will decrease false positives for aspergillosis
5.Determine thresholds to justify antifungal treatment	Develop treatment protocols based on estimated PPVs and NPVs, using team approach	Agree among clinical and stewardship services on likelihoods of aspergillosis that justify treatment, and how much potential antifungal overtreatment you are willing to tolerate
6.Individualize decisions in each patient	Make treatment decisions for each patient by considering clinical data and case details	In each patient, clinical parameters (eg, new findings, lack of alternative diagnoses, length of stay, etc), radiography (eg, new lesions), and laboratory data (eg, higher values, repeat or multiple positive results, etc) may refine assessments of disease likelihood and need for treatment

Abbreviations: CAPA, coronavirus disease 2019-associated pulmonary aspergillosis; COVID-19, coronavirus; ICU, intensive care unit; NPV, negative predictive value; PPV, positive predictive value.