I was 12 weeks, and my results came back 0.11cm and combine with my age risk group which was something like 1-1500 it came back with a result of 1-12000 .. so obvioulsy a great indication that all is ok..

The best time to go is around the 12 week mark for the ultrasound.. im not sure about the blood test.. i think they are around 16weeks from memory? Hopefully someone else can help you there !