Table 1 Metabolic testing in children with global developmental delay
| Reference | Class | N | Results (% patients with abnormal screening) |
|---|---|---|---|
| 33 | II | 151 | 26% for mild delay; 77% for severe delay; genetic etiology in 28%, 5% were metabolic disorders |
| 34 | III | 1,087 | 0.6%; standardized biochemical screening |
| 35 | III | 1,568 | 1.3%; standardized biochemical screening |
| 7 | III | 60 | 63% with all testing but less than 1% for metabolic testing |
| 36 | III | 281 | <5%; nonstandardized evaluation; etiologic yield of 72% for whole group |
| 28 | III | 99 | <5% even on an indicated basis |
| 37 | III | 118 | 13.6% using stepwise rather than routine screening protocol |