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. 2021 Apr 27:M21-0422. doi: 10.7326/M21-0422

Figure 2. Antigen test result, by SARS-CoV-2 nucleocapsid Ct values and virus culture result.

Figure 2.

Ct values of all RT-PCR–positive respiratory specimens (n = 105). Shown are nucleocapsid Ct values for all paired RT-PCR–positive specimens stratified by antigen-positive and antigen-negative results and further by virus culture results. Median Ct for each category of antigen results is noted by the black bar. Virus culture was attempted for all RT-PCR–positive specimens with Ct ≤34. Culture was attempted for 8 additional specimens that were antigen-positive and RT-PCR–negative; all were culture-negative. Randomized jitter of 0.5 was added to x-axis values to improve visibility. Antigen test: BinaxNOW COVID-19 Ag Card. Ct = cycle threshold; RT-PCR = reverse transcription polymerase chain reaction.