Fig. 1

False-positive Legionella pneumophila antibodies in COVID-19 patients A shows the comparison of demographic and clinical characteristics of the enrolled patients between two groups.  B shows the difference of IgM titers of SARS-CoV-2 between two groups. ^†Plus–minus values are means ± standard deviation. ^‡The categorical variables were compared using the Chi squared test or Fisher’s exact test. The continuous variables were compared using the Mann–Whitney U test or t test. A two-sided α of less than 0.05 was considered statistically significant. *Patients who received corticosteroids on the day of LP-IgM testing (prednisone equivalent dose). IgM Immunoglobulin M, LP Legionella pneumophila, APACHE Acute Physiology and Chronic Health Evaluation, COPD Chronic obstructive pulmonary disease, C_t cycle threshold, hsCRP High-sensitivity C-reactive protein