I got mine in the post around a week later, they will tell you babys nuchal fold (think that's how it's spelled) Measurement there and then well mine did. She told me what it had to be more than for a concern and mine was way way less, they factor age in too but if measurement is low chances are pretty slim. I got results back as 1 in 50000. Ask for measurement if not told this will hopefully relax you to you get results don't worry good look
It took about a week but I felt pretty confident before then because I had seen the nuchal fold measurement and it was tiny. I'm also young enough that I'm not high risk. Obviously I didn't know my blood test results until the midwife phoned with the combined results.
Mine was just over a week. I don't agree with the previous posters though, don't put too much faith in the nuchal fold measurement.
My NF measurement was 1.7, which is great, but my blood tests totally skewed it and I ended up with a 1 in 57 risk. My HCG levels are about 10 times high than normal, so blood can make a real difference.