Understanding cycle threshold (Ct) in SARS-CoV-2 RT-PCR
There are many different SARS-CoV-2 RT-PCR assays/platforms in use across the UK.
Each assay will have a slightly different limit of detection (LoD) – the lowest concentration of virus that can be reliably and consistently detected by the assay, and will be configured according to local arrangements. Some RT-PCRs are designed to identify a single gene target and others will detect multiple targets. Those detecting multiple targets can give greater certainty when interpreting results.