We cannot know: with rapid swabs we only have a qualitative indication. If the T line appears, even if just hinted at, the buffer to be read as positive And we have no indication of viral load. With such a result the person can be contagious – he replies Pierangelo Clerici, president of the Italian Clinical Microbiologists Association. A correlation between low viral load, therefore presumed lower contagiousness, and weak T band has never been demonstrated. In rapid tests there is no weak positive result as in molecular swabs: there is only positive or negative and by positive we mean any type of intensity or color. In fact, the devices are affected by many external factors such as storage (it must not stay warm); also important sampling: it must be done correctly. With only one sampling method, for example only nasal, there is the risk of having a less complete response if perhaps the virus is more present in the throat. It is possible that someone has a low viral load and a thin test line, but it is also possible that a person has a high viral load but for reasons inherent to the device a weak band appears: the non-standardizable correlation. In conclusion, it is not said at all that a faded line corresponds to a low viral load, therefore people must continue to implement the precautions we know well: wear a mask, isolate themselves and above all not have contact with fragile people.
8 September 2022 | 13:25
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