Question to the Department of Health and Social Care:

To ask the Secretary of State for Health and Social Care, if he will require all reporting of covid-19 PCR test results to include an estimated measure of viral burden.

We have no plans to do so. Cycle threshold (Ct) is a semi-quantitative value which can broadly categorise the concentration of viral genetic material in a patient sample as low, medium or high. The reporting of many laboratories, including the Lighthouse Laboratories, includes Ct values. However, a single Ct value in the absence of clinical context cannot be relied upon for decision making about a person’s infectivity. Ct values cannot be directly compared between assays of different types. Not all laboratories will use the same assay and some may use more than one.