Table 1.

General considerations for the diagnosis of hypoxemic acute respiratory failure (ARF) in immunocompromised patients

1.	Diagnostic tests should be selected based on a clinical assessment of the most likely cause(s) of ARF. This assessment relies on the clinical and radiological presentation and on the nature of the underlying condition
2.	A clinical suspicion for a given diagnosis must be confirmed by the most appropriate diagnostic strategy. A differential diagnosis should always be considered and assessed as appropriate
3.	All immunocompromised patients with suspected respiratory infection should undergo a minimal diagnostic workup that must include a chest X ray, standard blood tests (blood cell counts, electrolytes, renal function test, liver enzymes, LDH level, and hemostasis parameters), blood cultures, sputum examination for bacteria, echocardiography, urine bacterial antigens, and viral PCRs on nasal swabs or nasopharyngeal aspirates
4.	When diagnostic yields are similar non-invasive diagnostic tests should be preferred over fiberoptic bronchoscopy with bronchoalveolar lavage (FOB/BAL)
5.	A positive test is not necessarily diagnostic (false-positives, colonization)
6.	A negative test is sometimes diagnostic
7.	When the initial evaluation suggests that a disease is unlikely, a test with a high negative predictive value should be preferred
8.	When the initial evaluation suggests that a disease is likely, a test with high sensitivity should be preferred
9.	When selecting the diagnostic strategy, the risk/benefit ratio must be assessed. FOB/BAL should be reserved for situations in which this approach has a high diagnostic yield (organ transplantation, associated HIV infection, systemic inflammatory joint disease, high probability of Pneumocystis pneumonia, diffuse ground-glass opacities) and discouraged in other situation (patients with malignancies, neutropenia, alveolar consolidations, or bronchial/bronchiolar disease)
10.	Patients with respiratory distress and/or severe hypoxemia are at risk for respiratory deterioration following FOB/BAL. Non-invasive tests should be preferred. If FOB/BAL is indicated by the bedside physicians, high-flow nasal oxygen should be considered. Whether patients should be intubated for the procedure questions about the risk/ratio benefit and remains unsure for the authors