Threshold values for chromosome specific probe sets
| Probe set | Sample set | n | Mean | SD | Threshold mean+3SD |
|---|---|---|---|---|---|
| *As inter- and intra-assay variation was the same, data from replicate assays have been used to determine means/SDs for abnormal populations. | |||||
| Chromosome 13 | Trisomy 13 | 5* | 1.34 | 0.076 | 1.11 (1.57) |
| Normal | 474 | 1.016 | 0.054 | 0.85 (1.18) | |
| Chromosome 18 | Trisomy 18 | 10* | 1.36 | 0.073 | 1.14 (1.58) |
| Normal | 474 | 1.023 | 0.049 | 0.87 (1.17) | |
| Chromosome 21 | Trisomy 21 | 22* | 1.38 | 0.081 | 1.13 (1.62) |
| Normal | 474 | 1.011 | 0.048 | 0.86 (1.16) | |
| Chromosome X (female) | Normal | 239 | 1.00 | 0.075 | 0.77 (1.23) |
| Chromosome X (male) | Normal | 235 | 1.00 | 0.11 | 0.67 (1.33) |
| Chromosome Y | Normal | 235 | 1.01 | 0.11 | 0.68 (1.34) |