You are presented with a paragraph from a COVID-19 literature. Classify the topics of this piece of text by choosing from the following categories:

- Epidemic Forecasting: The content relates to predictions about the spread of COVID-19.
- Treatment: The paragraph discusses therapeutic methods or medication for COVID-19.
- Prevention: The content covers measures to prevent the spread of COVID-19.
- Mechanism: The paragraph explains the biological mechanisms of the virus.
- Case Report: The content is a report of a COVID-19 case.
- Transmission: The paragraph discusses how COVID-19 is transmitted.
- Diagnosis: The content is about diagnosing COVID-19 in individuals.

Your classification should be provided as an element within a JSON array. The array should be formatted with topics enclosed in double quotes and separated by commas, following the JSON format, for example: ["Topic1", "Topic2", ...]. Include all applicable topics within the array. Your output should be a valid JSON array, and no additional text should be included in your response.

Article:

BACKGROUND: Guidelines recommend maximal efforts to obtain blood and sputum cultures in patients with COVID-19, as bacterial coinfection is associated with worse outcomes. The aim of this study was to evaluate the yield of bacteriological tests, including blood and sputum cultures, and the association of multiple biomarkers and the Pneumonia Severity Index (PSI) with clinical and microbiological outcomes in patients with COVID-19 presenting to the emergency department (ED). METHODS: This is a substudy of a large observational cohort study (PredictED study). The PredictED included adult patients from whom a blood culture was drawn at the ED of Haga Teaching Hospital, The Netherlands. For this substudy, all patients who tested positive for SARS-CoV-2 by PCR in March and April 2020 were included. The primary outcome was the incidence of bacterial coinfection. We used logistic regression analysis for associations of procalcitonin, C reactive protein (CRP), ferritin, lymphocyte count and PSI score with a severe disease course, defined as intensive care unit admission and/or 30-day mortality. The area under the receiver operating characteristics curve (AUC) quantified the discriminatory performance. RESULTS: We included 142 SARS-CoV-2 positive patients. On presentation, the median duration of symptoms was 8 days. 41 (29%) patients had a severe disease course and 24 (17%) died within 30 days. The incidence of bacterial coinfection was 2/142 (1.4%). None of the blood cultures showed pathogen growth while 6.3% was contaminated. The AUCs for predicting severe disease were 0.76 (95% CI 0.68 to 0.84), 0.70 (0.61 to 0.79), 0.62 (0.51 to 0.74), 0.62 (0.51 to 0.72) and 0.72 (0.63 to 0.81) for procalcitonin, CRP, ferritin, lymphocyte count and PSI score, respectively. CONCLUSION: Blood cultures appear to have limited value while procalcitonin and the PSI appear to be promising tools in helping physicians identify patients at risk for severe disease course in COVID-19 at presentation to the ED.
["Diagnosis", "Treatment"]