My wife is required to submit to weekly testing for the coof. I asked the testing facility what Cycle Threshold they use for their tests. Here is the response:
**Our test does not use cycle thresholds (Ct). Ct is used for a qPCR test method, whereas we perform rRT-PCR. Our detection is given by flourescently tagged molecules that generate Median Fluorescent Intensity (MFI) based on the viral load of the collected sample. We test for multiple genes within the SARS-CoV-2 genome and have a different threshold for each. I hope that answers your question. **
I 'think' I understand but perhaps there is an anon in here that can give a brief explanation regarding accuracy etc.
rRT-PCR for SARS-CoV-2: Analytical considerations
βThe amplification curves are important to determine exact baseline and threshold. RRT-PCR results for positive COVID-19 should have a CT less than 40, and the results more than 40 should be considered as negative result. Samples with a CT values of 37β40 must be re-sampled.β
https://pubmed.ncbi.nlm.nih.gov/33485902/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7826022/pdf/main.pdf