LFTs are for picking it up in asymptomatic people, as I understand it then if you have symptoms then PCR is what you need. (See first statements at
https://www.nhs.uk/conditions/coronavirus-covid-19...).
Either way, hope you are okay and your sister recovers quickly!
Ah, I had understood—incorrectly, I guess—that LFTs were the first step and PCRs were used to confirm a positive LFT. I hadn't thought of going straight to PCR.
Plot twist: PCR (administered yesterday) came back negative.
Conversely, my sister who is still symptomatic took another LFT this morning and was positive.