Viral load can vary based on the type of specimen collected and how much specimen is collected. External variables can influence CT values, including specimen transport, specimen storage conditions, how many times a specimen is frozen/thawed, and the instrument on which testing is performed. It is still unknown how much virus is needed to transmit the virus from person-to-person and cause new infections. Since CT values can vary based on many factors, it is not a good indicator of how infectious a person is or how much virus is present in a person (also known as viral load). The CT value can also change based on the sta ge of infection, as the amount of virus present in a person can vary during the course of their illness. A specimen may have a higher CT value (low viral load) if the patient is in their early infection and the virus is still increasing in their body, or in later stage of infection when the viral load is decreasing. In both these examples, a CT value still represents detection of the virus and that person would still be considered positives for SARS-CoV-2.