Background: COVID-19 is diagnosed via Real Time Reverse Transcription Polymerase Chain Reaction (RT-PCR), with plain chest CT and chest x-ray as adjuncts. In the Philippines, chest x-ray is used as initial screening in assessing potential COVID-19 cases, with plain chest CT scan not routinely used due to higher cost and decreased availability. Objective: This study determined the validity of chest x-ray and plain chest CT as initial screening tools for admitted COVID-19 patients from March 1 to November 30, 2020, at San Lazaro Hospital, comparing these with RT-PCR testing for COVID-19 as initial basis for considering a patient as a possible case of COVID-19. Methods: This was a cross-sectional study of radiographic literature of admitted COVID-19 patients from March 1 to November 30, 2020, at San Lazaro Hospital, all with confirmatory RT-PCR, chest X-rays, and plain chest CTs. Baseline chest x-rays, with initial plain chest CT results, were compared with RT-PCR results. A tally was made, noting radiographic findings on both Chest X-ray and Plain Chest CT most frequently seen among patients with corresponding positive real time RT-PCR results. Results: Chest X-rays done < 2 days from admission revealed involvement of both lungs, with infiltrates located centrally and peripherally, with major predilection for both lower lobes. Plain chest CT was similar, with ground glass opacities as the most common finding, consolidation second. Chest x-ray had a sensitivity of 88.11%, plain chest CT 94.71%. Sensitivity of combined chest x-ray and plain chest CT was 86.78%. Specificity and predictive value were not computed due to non-inclusion of admitted patients with COVID negative RT-PCR swab. Conclusion Chest X-ray and plain chest CT are useful modalities with high sensitivity in screening patients with fever, cough, and colds on admission. However, initial chest x-ray and plain chest CT scan results do not translate into a prognosis without context of initial diagnostics and management done during confinement.
COVID-19 ; X-Rays ; COVID-19 Testing