Pragmatic Recommendations for the Use of Diagnostic Testing and Prognostic Models in Hospitalized Patients with...

Management of patients with severe or critical COVID-19 is mainly modeled after care of patients with severe pneumonia or acute respiratory distress syndrome from other causes. These models are based on evidence that primarily originates from investigations in high-income countries, but it may be impractical to apply these recommendations to resource-restricted settings in low- and middle-income countries (LMICs). We report on a set of pragmatic recommendations for microbiology and laboratory testing, imaging, and the use of diagnostic and prognostic models in patients with severe COVID-19 in LMICs. For diagnostic testing, where reverse transcription-PCR (RT-PCR) testing is available and affordable, we recommend using RT-PCR of the upper or lower respiratory specimens and suggest using lower respiratory samples for patients suspected of having COVID-19 but have negative RT-PCR results for upper respiratory tract samples. We recommend that a positive RT-PCR from any anatomical source be considered confirmatory for SARS-CoV-2 infection, but, because false-negative testing can occur, recommend that a negative RT-PCR does not definitively rule out active infection if the patient has high suspicion for COVID-19. We suggest against using serologic assays for the detection of active or past SARS-CoV-2 infection, until there is better evidence for its usefulness. Where available, we recommend the use of point-of-care antigen-detecting rapid diagnostic testing for SARS-CoV-2 infection as an alternative to RT-PCR, only if strict quality control measures are guaranteed. For laboratory testing, we recommend a baseline white blood cell differential platelet count and hemoglobin, creatinine, and liver function tests and suggest a baseline C-reactive protein, lactate dehydrogenase, troponin, prothrombin time (or other coagulation test), and D-dimer, where such testing capabilities are available. For imaging, where availability of standard thoracic imaging is limited, we suggest using lung ultrasound to identify patients with possible COVID-19, but recommend against its use to exclude COVID-19. We suggest using lung ultrasound in combination with clinical parameters to monitor progress of the disease and responses to therapy in COVID-19 patients. We currently suggest against using diagnostic and prognostic models as these models require extensive laboratory testing and imaging, which often are limited in LMICs.