Why is there concern over the sample being at room temperature? Why can’t I put it in the fridge/freezer?

Why is there concern over the sample being at room temperature? Why can’t I put it in the fridge/freezer?

The cell-free DNA (cfDNA) blood collection tubes used to collect OncoK9 samples have an anticoagulant as well as a preservative to stabilize cells. This prevents the cells in the sample from lysing (breaking apart) and releasing their cellular contents (including genomic DNA) into the plasma. When a sample is exposed to cold temperatures, the preservative’s ability to prevent cell lysis is impaired. When white blood cells lyse, they release their genomic DNA into the plasma, which makes it harder to find any cancer-derived cfDNA; the hemoglobin from the lysed red blood cells can also interfere with the analysis.