You asked
Please can you provide the Cycle Thresholds for positive Covid tests in the UK since January 2020. This is the number of times the sample is amplified before it gives a positive result.
We said
Thank you for your request.
The Covid Infection Survey (CIS) is a community study which began on the 26 April 2020 and regularly tests a representative sample of the UK population to register the percentage of people testing positive for COVID in the survey and use this to infer information about the wider UK population. As such, we do not hold fuller information on every test conducted in the UK since January 2020, only those tests that are conducted on the participants from our study.
On Tab 6a of the dataset accompanying the latest bulletin, you will find the mean Cycle Threshold (Ct) values alongside the 10th, 25th, 50th, 75th and 90th percentile Ct values for the positive tests returned by our study each week. These data on Ct values start from the week commencing the 21 September 2020.
For more information on Ct values since the start of the survey, please see the paper by our partner researchers in collaboration with the CIS team.