Help with Stats

I am assessing the impact a new analyser has on the detection of a blood mutation, JAK2, involved in blood cancer. The old method had a detection limit to 0.5%. The new one detects down to 0.01%. There off a lot more mutations are being found. The significance of these mutations at very low level though is unclear. I have collected data showing that at low level <0.5% isn’t always associated with a blood cancer based on bone marrow biopsy. I want to compare the 2 groups (>0.5% and <0.5%) for any statistical differences in blood counts and try to determine if there is a mutation cut off that indicates cancer vs no cancer