Sensitivity and specificity of MCV+MCH and HbA2 levels for thalassaemia carriers screened by NGS
| MM and HbA2 | Sensitivity (95% CI) | Specificity (95% CI) | PPV (95% CI) | NPV (95% CI) | True positive | False positive | True negative | False negative |
| α thalassaemia | 61.05% (53.33% to 68.38%) | 87.65 % (84.05% to 90.70%) | 67.74% (61.21% to 73.64%) | 84.12 % (81.41% to 86.51%) | 105 | 50 | 355 | 67 |
| αα/--SEA | 86.81% (78.10% to 93.00%) | 84.36% (80.82% to 87.48%) | 50.97% (45.44% to 56.47%) | 97.16 % (95.27% to 98.30%) | 79 | 76 | 410 | 12 |
| αα/-α3.7 | 34.21% (19.63% to 51.35%) | 73.65% (69.72% to 77.33%) | 8.39% (5.45% to 12.70%) | 94.08 % (92.62% to 95.26%) | 13 | 142 | 397 | 25 |
| αα/-α4.2 | 37.50% (15.20% to 64.57%) | 73.44% (69.58% to 77.05%) | 3.87% (2.06% to 7.14%) | 97.63 % (96.56% to 98.37%) | 6 | 149 | 412 | 10 |
| β thalassaemia | 98.51% (91.96% to 99.96%) | 99.61 % (98.59% to 99.95%) | 97.06% (89.22% to 99.25%) | 99.8 % (98.64% to 99.97%) | 66 | 2 | 508 | 1 |
| Codons 41/42 (-TTCT) | 96.55% (82.24% to 99.91%) | 92.7 % (90.19% to 94.73%) | 41.18% (34.01% to 48.74%) | 99.8% (98.67% to 99.97%) | 28 | 40 | 508 | 1 |
| IVS-II-654 (C>T) | 100.00% (76.84% to 100.00%) | 90.41 % (87.67% to 92.71%) | 20.59% (16.75% to 25.04%) | 100.00 % | 14 | 54 | 509 | 0 |
| −28 (A>G) | 100.00% (59.04% to 100.00%) | 89.3 % (86.47% to 91.71%) | 10.29% (8.30% to 12.70%) | 100.00 % | 7 | 61 | 509 | 0 |
| Codon 17 (A>T) | 100.00% (63.06% to 100.00%) | 89.46 % (86.64% to 91.86%) | 11.76% (9.50% to 14.48%) | 100.00% | 8 | 60 | 509 | 0 |
CI, Confidence interval; MCH, mean corpuscular haemoglobin; MCV, mean corpuscular volume; MM, MCV and MCH; NGS, next-generation sequencing; NPV, negative predictive value; PPV, positive predictive value.