Table 2.
Outcomes for positive and non-reportable cfDNA results for chromosomes 21, 18, 13
| All | T21 | T18 | T13 | Triploidy | >1* | NR | p | |
|---|---|---|---|---|---|---|---|---|
| n | 105 | 48 | 22 | 17 | 2 | 3 | 13 | |
| Serum Screening | 56 | 24 | 9 | 8 | 2 | 1 | 12 | <0.001 |
| FTS | 39/56 (69.6) | 23 (95.8) | 8 (88.9) | 4 (50.0) | 1 (50.0) | 1 (100) | 3 (25.0) | |
| IS | 11/56 (19.6) | 0 | 1 (111) | 2 (25.0) | 1 (50.0) | 0 | 7 (58.3) | |
| QS | 6/56 (10.7) | 1 (4.2) | 0 | 2 (25.0) | 0 | 0 | 2 (16.7) | |
| Serum Screen Positive‡ | 29/56 (51.8) | 17 (70.8) | 7 (77.8) | 3 (37.5) | 0 | 0 | 2 (16.7) | 0.004 |
| Abnormal US findings | ||||||||
| 1st TM US | 45/97 (46.4) | 25/45 (55.6) | 13/20 (65.0) | 6/14 (42.9) | 0/2 | 0/3 | 1/13 (7.7) | 0.003 |
| NT ≥3.5mm | 28/91 (30.8) | 13/41 (31.7) | 11/18 (61.1) | 3/14(21.4) | 0/2 | 0/3 | 1/13 (7.7) | 0.019 |
| 2nd TM US | 7/42 (16.7) | 3/13 (23.1) | 1/8 (12.5) | 2/10 (20) | 0/1 | 0/1 | 1/9 (11.1) | 0.963 |
| Repeat cfDNA | 11/105 (10.5) | 2 (4.2) | 0 | 0 | 2 (100) | 0/3 | 7 (53.9) | <0.001 |
| Diagnostic Testing | 84/103 (81.6) | 43/47 (91.5) | 19/22 (86.4) | 15/17 (88.2) | 0/2 | 3/3 (100) | 4/13 (30.8) | <0.001 |
| CVS | 70/103 (68.0) | 38/47 (80.9) | 15/22 (68.2) | 12/17 (70.6) | NA | 3/3 | 2/12 (16.7) | |
| Amniocentesis | 14/103 (13.6) | 5/47 (10.6) | 4/22 (18.2) | 3/17 (17.7) | NA | 0 | 2/12 (16.7) | |
| Abnormal Genetics | ||||||||
| Karyotype | 60/84 (71.4) | 37/43 (86.1) | 12/19 (63.2) | 8/15 (53.3) | NA | 2/3 (66.7) | 1/4 (25.0) | 0.010 |
| Microarray | 2/6 (33.3) | 0/1 | 1/3 | 1/1 | NA | NA | 0/1 | >0.999 |
| Pregnancy Outcome | <0.001 | |||||||
| TOP | 62/105 (59.1) | 37/48 (77.1) | 14/22 (63.6) | 8/17 (47.1) | 0/2 | 2/3 (66.7) | 1/13 (7.7) | |
| Spontaneous loss | 5/105 (4.8) | 2/48 (4.2) | 1/22 (4.6) | 1/17 (5.9) | 0/2 | 0/3 | 1/13 (7.7) | |
| Delivered | 35/105 (33.3) | 9/48 (18.8) | 4/22 (18.2) | 8/17 (47.1) | 2/2 | 1/3 (33.3) | 11/13 (84.6) | |
| Lost to follow-up | 3/105 (2.9) | 0/48 | 3/22 (13.6) | 0/17 | 0/2 | 0/3 | 0/13 | |
| No confirmed outcome | 7 | 3 | 3 | 1 | 0 | 0 | 0 | |
| Confirmed aneuploidy§ | 62/98 (63.3) | 38/45 (84.4) | 12/19 (63.2) | 9/16 (56.3) | 0/2 | 2/3 (66.7) | 1/13 (7.7) | <0.001 |
Values are n (%). 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; FTS, first trimester screening; IS, integrated screening; QS, quad screening; TM, trimester; US, ultrasound; NT, nuchal translucency; CVS, chorionic villus sampling; TOP, termination of pregnancy.
>1 parameter was abnormal (ie: trisomy AND microdeletion, trisomy AND sex chromosome, trisomy AND NR, etc.)
As determined by the California state prenatal screening program
Confirmed by karyotype and/or postnatal evaluation.