Table 1.

Characteristics of patients with positive and non-reportable cfDNA results for chromosomes 21, 18, 13

	All	T21	T18	T13	Triploidy	>1*	NR	p
n (%)	105	48 (45.7)	22 (21.0)	17 (16.2)	2 (1.9)	3 (2.9)	13 (12.4)
Median age in years (range)	38 (27–48)	38 (29–47)	39 (27–48)	38 (30–45)	42 (40–44)	34 (31–37)	35 (29–41)	0.007
AMA	87 (82.9)	42 (87.5)	20 (90.9)	15 (88.2)	2 (100)	1 (33.3)	7 (53.9)	0.017
IVF	17/103 (16.5)	5/47 (10.6)	3/21 (14.3)	4(23.5)	2 (100)	0	3 (23.1)	0.066
Twins	10 (9.5)	4(8.3)	1 (4.6)	3 (17.7)	1 (50.0)	0	1 (7.7)	0.307
Laboratory (n)								0.006
1	37 (35.2)	17 (35.4)	10 (45.5)	7 (41.2)	0	0	3 (23.1)
2	38 (36.2)	22 (45.8)	9 (40.9)	5 (29.4)	0	1 (33.3)	1 (7.7)
3	28 (26.7)	8 (16.7)	2 (9.1)	5 (29.4)	2 (100)	2 (66.7)	9 (69.2)
4	2 (1.9)	1 (2.1)	1 (4.6)	0	0	0	0
Platformˆ								<0.001
MPS	75 (71.4)	39 (81.3)	19 (86.4)	12 (70.6)	0	1 (33.3)	4 (30.8)
SNP	28 (26.7)	8 (16.7)	2 (9.1)	5 (29.4)	2 (100)	2 (66.7)	9 (69.3)
TS	2 (1.9)	1 (2.1)	1 (4.6)	0	0	0	0

Values are n (%) unless otherwise indicated. If values were missing for certain parameters, the denominator is indicated. P-values were calculated by Kruskal-Wallis or Fisher’s exact test. Statistically significant p-values (defined as p<0.05) are indicated in bold.

Abbreviations: cfDNA, cell-free fetal DNA; T21, trisomy 21; T18, trisomy 18; T13, trisomy 13; NR, non-reportable; AMA, advanced maternal age; IVF, in vitro fertilization; MPS, massive parallel sequencing; SNP, single nucleotide polymorphism; TS, targeted sequencing.

^*>1 parameter was abnormal (ie: trisomy AND microdeletion, trisomy AND sex chromosome, trisomy AND NR, etc.)

^ˆMPS is used by Laboratories 1 and 2; SNP sequencing/microarray by Laboratory 3; TS by Laboratory 4.