I was invited to take part in the NHS bowel cancer screening programme. I put my stools sample in the prepaid envelope supplied (Royal Mail 48 tracked) and posted it today. I realised just after I'd dropped it in the box this afternoon that I’d missed the last collection time (11:30am on Saturday) so now it's going to sit there until Monday. The instructions just said to post it - no deadline was mentioned. Does anyone know whether these samples have to be received by the lab within a certain time to get an accurate result?