teachings herein contemplates a method for isolating and testing cell free fetal dna from maternal plasma the method may be performed on a single sample or on a multitude of samples e g in a multi well plate the method may include contacting the maternal plasma sample with a protective agent the protective agent may include a fixative as previously discussed so that the maternal cells remain intact throughout the blood draw and dna isolation process the protective agent may further include a dnase inhibitor to maintain the structural integrity of the fetal dna after contacting the maternal plasma sample with the protective agent the sample may be centrifuged to separate the plasma and the supernatant is discarded by contacting a maternal blood sample with the protective agent the blood sample does not necessarily require immediate processing and may be stored for a prolonged period such as up to about 14 days or longer at room temperature thus the inventions herein contemplate one or more steps of storing and or otherwise waiting a relatively lengthy period from the time of blood draw and or contacting until the time of screening testing or other analysis once the sample is processed an appropriate concentration of an agent for inducing precipitation e g a composition of salt and or alcohol may be added to precipitate the fetal dna containing material an organic or other compound such as a phenol derivative or the like may be added to remove any remaining protein contaminants any protein contaminants that still remain may be removed by adding additional amounts of an organic or other compound such as a phenol derivative or the like after centrifugation ethanol may be added and the.