Evaluation of Sample Stability and Automated DNA Extraction for Fetal Sex Determination Using Cell-Free Fetal DNA in Maternal Plasma

Table 1

Efficiencies of manual and automated cfDNA extractions. Despite consistently producing higher Ct values (lower cfDNA amounts), automated DNA extraction of samples collected in the 1st trimester of pregnancies produced cfDNA amounts well within the detection limits of rtPCR.

	Manual DNA extraction; (QIAGEN DSP) 𝑁=50	Automated DNA extraction; (COBAS AmpliPrep) 𝑁=108
Ct values	34,31–44,87; (36,59)	34,17–46; (37,74)
cfDNA amounts (GE/mL)	259,43; (61,05–725,33)	107,35; (10,28–327,06)