Ever since the COVID-19 pandemic began, battles have raged over-testing: Which tests should be given, to whom, and how often? Now, epidemiologists and public health experts are opening a new debate. They say testing centres should report whether a person is positive but also a number known as the cycle threshold (CT) value, which indicates how much of a virus load does an infected person harbour.
In case you wish to know more:
Remember, samples that turn out positive can start out with vastly different amounts of virus, for which the CT value provides an inverse measure.
If a higher number of cycles is needed – hence a higher CT value – it means that the amount of virus, otherwise known as viral load, is low. This is because the virus is spotted only after many cycles.
CT value can be used as an estimate of transmission potential. Patients with a low CT value (high viral load) will be actively shedding the virus and likely to still be infectious, while patients with high CT value (low viral load) might be recovered individuals who are no longer infectious, as they are shedding very minute quantities of virus.
A high CT value, typically above 30, suggests that it is not a recent infection. Thus, the CT value also gives us a clue if one has recovered from COVID-19 infection.
CT > 30 = Suggests Not a Recent Infection
Regardless of the debate on “CT”, early detection is most critical in breaking the viral transmission chain. If you’ve been exposed to someone with COVID-19 or begin to experience symptoms of the disease, seek medical care early.