A Research Study Is Conducted Using Newborn Screening Samples Analyzed

A research study is conducted using newborn screening samples analyzed and stored over two years at a state health department.Study results are inconsistent and erratic.What are the likely reasons for this variability?

A) Differences in the way samples were originally collected
B) Degradation of the samples over time
C) Contamination from the original analysis
D) Inexperience using newborn screening samples
E) High numbers of conditions screened in these samples