Hello from Argentina. In a previous consultation on the performance of the diagnostic PCR test, it was answered that the test was performed on nasopharyngeal material and blood. Has the presence of the virus been shown in blood? Is this test useful? / 您好，上次一个关于PCR诊断如何进行的问题种得到的回复说检查是对鼻咽取样和血液取样进行的。血液中能检测到病毒存在是嘛？这种检测方法能否用于诊断？