Table 4.
Test Characteristics of Selected HC Percentile Thresholds for Diagnosing Children with IEC, MGCM, or BESS
| A | B | C | D | E | G | H | I | K | L | M | N |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Threshold | Number in source population | Number diagnosed with IEC, MGCM, or BESS | Number above threshold | Number above threshold with IEC, MGCM, or BESS |
Sensitivity E/C |
Specificity (B-C-(D-E))/(B-C) |
Positive predictive value E/D |
Likelihood ratio positive G/(1-H) |
Likelihood ratio negative (1-G)/H |
Number Needed to Screen B/E |
Number Needed to Test D/E |
| Above CDC 95th | 74,428 | 324 | 12,325 | 221 | 68% | 84% | 1.8% | 4.2 | 0.4 | 337 | 56 |
| Above WHO 95th | 74,428 | 324 | 18,528 | 242 | 75% | 75% | 1.3% | 3.0 | 0.3 | 308 | 77 |
| Above PCN 95th | 74,428 | 324 | 7,694 | 193 | 60% | 90% | 2.5% | 5.9 | 0.4 | 386 | 40 |
| Above CDC 97th | 74,428 | 324 | 8,373 | 203 | 63% | 89% | 2.4% | 5.7 | 0.4 | 367 | 41 |
| Above WHO 97th | 74,428 | 324 | 13,275 | 225 | 69% | 82% | 1.7% | 3.9 | 0.4 | 331 | 59 |
| Above PCN 97th | 74,428 | 324 | 4,532 | 167 | 52% | 94% | 3.7% | 8.8 | 0.5 | 446 | 27 |
| Above CDC 99.6th | 74,428 | 324 | 2,030 | 129 | 40% | 97% | 6.4% | 15.5 | 0.6 | 577 | 16 |
| Above WHO 99.6th | 74,428 | 324 | 3,438 | 155 | 48% | 96% | 4.5% | 10.8 | 0.5 | 480 | 22 |
| Above PCN 99.6th | 74,428 | 324 | 711 | 69 | 21% | 99% | 9.7% | 24.6 | 0.8 | 1,079 | 10 |
| Crossed 2 IMPL-CDC | 64,015 | 321 | 29,206 | 223 | 69% | 54% | 0.8% | 1.5 | 0.6 | 287 | 131 |
| Crossed 2 IMPL-WHO | 64,015 | 321 | 22,462 | 162 | 50% | 65% | 0.7% | 1.4 | 0.8 | 395 | 139 |
| Crossed 2 IMPL-PCN | 64,015 | 321 | 13,831 | 156 | 49% | 79% | 1.1% | 2.3 | 0.7 | 410 | 89 |
| Crossed 4 IMPL-CDC | 64,015 | 321 | 5,727 | 103 | 32% | 91% | 1.8% | 3.6 | 0.7 | 622 | 56 |
| Crossed 4 IMPL-WHO | 64,015 | 321 | 4,372 | 66 | 21% | 93% | 1.5% | 3.0 | 0.9 | 970 | 66 |
| Crossed 4 IMPL-PCN | 64,015 | 321 | 1,703 | 55 | 17% | 97% | 3.3% | 6.7 | 0.8 | 1,143 | 30 |
| Crossed 6 IMPL-CDC | 64,015 | 321 | 490 | 17 | 5% | 99% | 3.5% | 7.1 | 1.0 | 3,766 | 29 |
| Crossed 6 IMPL-WHO | 64,015 | 321 | 556 | 17 | 5% | 99% | 3.1% | 6.3 | 1.0 | 3,766 | 33 |
| Crossed 6 IMPL-PCN | 64,015 | 321 | 130 | 10 | 3% | > 99% | 7.7% | 16.5 | 1.0 | 6,402 | 13 |
IEC (intracranial expansive condition); MGCM (metabolic or genetic condition associated with macrocephaly); BESS (benign enlargement of the subarachnoid spaces); CDC (Centers for Disease Control head circumference growth curves); WHO (World Health Organization head circumference growth curves); PCN (primary care network head circumference growth curves); IMPL (increasing multiple percentile lines). The negative predictive value (C-(D-E))/(C-D) was 99.9% for all thresholds.