Of the specimens collected, bronchoalveolar lavage fluid specimens demonstrated the highest positive rates of at 93% (n = 14). This was followed by sputum at 72% (n = 75), nasal swabs at 63% (n = 5), fibrobronchoscope brush biopsy at 46% (6/13), pharyngeal swabs at 32% (n = 126), feces at 29% (n = 44) and blood at 1% (n = 3). The authors of that study pointed out that testing of specimens from multiple sites may improve the sensitivity and reduce false-negative test results.

In another study published in Radiology, which was titled  “Correlation of Chest CT and RT-PCR Testing in Coronavirus Disease 2019 in China,” investigators found chest CT achieved higher sensitivity for diagnosis of COVID-19 as compared with initial RT-PCR from pharyngeal swab samples. This retrospective study analyzed 1014 hospitalized patients with suspected COVID-19 in Wuhan, China—with patients undergoing both serial RT-PCR testing and chest CT.