Mae profion llif unffordd yn canfod presenoldeb antigen feirysol Covid-19 o sampl swab.  Dyfeisiau llaw yw LFTs sy'n cynhyrchu canlyniadau o fewn 20 i 30 munud, gyda'r potensial i gael eu hunan-weinyddu. Maent yn cael eu treialu i'w defnyddio mewn ysgolion a phrifysgolion, i bobl sy'n ymweld â chartrefi gofal ac yn y rhaglen profi torfol bresennol ym Merthyr.
Lateral flow testing detects the presence of the Covid-19 viral antigen from a swab sample.  LFTs are handheld devices which produce results within 20 to 30 minutes, with the potential to be self-administered. They are being piloted for use in schools and universities, for people visiting care homes and in the current mass testing programme in Merthyr.