BACKGROUND: Lung involvement in COVID-19 can be quantified by chest CT scan with some triage and prognostication value. At least 7 CT-severity score (CTSS) systems have been proposed. PURPOSE: We evaluated triage and prognostication performance of seven different CTSSs for COVID-19. MATERIALS AND METHODS: COVID-19, PCR positive patients admitted from February 20th 2020 to July 22^nd were included into a retrospective study. Demographic data and clinical data indicating disease severity at presentation and in peak disease severity were recorded. CT images were reviewed and scored according to seven different scoring systems (CTSS1-CTSS7) by two radiologists. Interrater reliability was determined for each CTSS. Then clinical severity of the disease at presentation (for triage) and peak disease severity (for outcome) were compared with CTSSs separately. ROC curves for performance of each CTSS in diagnosing severe/critical disease on admission, severe/critical disease at peak disease severity and critical disease at peak severity were plotted. Areas under the curve (AUCs), best thresholds and corresponding sensitivities and specificities were calculated. RESULTS: 96 patients were included with mean age of 63.6 ± 17.4 years (range: 21-88, median: 67). 57 (59,4%) were men and 39 (40.6%) were women. All CTSSs showed good interrater reliability as calculated intraclass correlation coefficients (ICCs) were 0.764-0.837 for all of the CTSSs. Only three CTSSs showed acceptable AUCs (AUC =0.7) for triage of severe/critical patients. All CTSSs showed acceptable AUCs for prognostication (AUCs=0.76-0.79). Calculated AUCs were not significantly different for triage and for prediction of severe/critical disease but some difference was shown for prediction of critical disease. CONCLUSION: Men are probably affected more frequently than women by COVID19. CTSS performance in triage was much lower than earlier reports and only three CTSSs showed acceptable AUCs. CTSS performed better for prognostic purposes than for triage as all 7 CTSSs showed acceptable AUCs in both types of prognostic ROC curves. Our results are compatible with those of recent studies. There is not much difference among performance of different CTSSs.