Table 3.

Predictors of percent change in cf-DNA content over the study period (n = 93)

Parameter	Correlation		Linear regression analysis
	coefficient (r)	p value	r 2	β	p value
PRBC volume	0.446	0.000*	NS
Supernatant volume	0.223	0.002*	NS
RBC content	0.321	0.000*	0.092	0.221	0.000*
Platelet content	−0.374	0.001*	0.160	−0.248	0.000*
WBC content	0.498	0.000*	0.182	0.165	0.000
Hemoglobin content	0.403	0.000*	NS
Hematocrit unit	0.104	0.159	NS

NS, not significant. Correlation coefficient and p value according to Spearman's rank correlation.

^*Statistically significant.