In March 2012 , 6000 unscreened women aged 30-65 years , living in a French region covered by a screening programme , who had not responded to an initial invitation to have a Pap smear were equally randomised to three groups : ` no intervention ' ; ` recall ' , women received a letter to have a Pap smear ; and ` self-sampling ' , women received a self-sampling kit to return to a centralised virology laboratory for PCR-based HPV testing .