Table 4. The sensitivity and specificity of different cut-off levels.
| Cut-off (ng/ml) | No. of trials | No. of patients | Sensitivity | Specificity |
|---|---|---|---|---|
| All | 35 | 9546 | 0.688(95%CI: 0.627- 0.743) | 0.922(95%CI: 0.890- 0.944) |
| 10 | 29 | 8323 | 0.688(95%CI: 0.621- 0.748) | 0.918(95%CI: 0.879- 0.946) |
| 12.5 | 24 | 7208 | 0.684(95%CI: 0.605- 0.754) | 0.919(95%CI: 0.689- 0.951) |
| 15 | 20 | 6098 | 0.668(95%CI: 0.570- 0.753) | 0.933(95%CI: 0.880- 0.963) |
| 20 | 12 | 4379 | 0.663(95%CI: 0.498- 0.797) | 0.958(95%CI: 0.897- 0.983) |
| 25 | 6 | 2750 | 0.733(95%CI: 0.416- 0.914) | 0.986(95%CI: 0.943- 0.997) |
| Europe | ||||
| 10 | 18 | 6420 | 0.730(95%CI: 0.661- 0.790) | 0.933(95%CI: 0.899- 0.956) |
| 12.5 | 15 | 5681 | 0.723(95%CI: 0.636- 0.796) | 0.940(95%CI: 0.900- 0.964) |
| 15 | 12 | 4745 | 0.723(95%CI: 0.604- 0.817) | 0.953(95%CI: 0.912- 0.975) |
| 20 | 7 | 3607 | 0.745(95%CI: 0.511- 0.891) | 0.969(95%CI: 0.908- 0.990) |
| 25 | 5 | 2442 | 0.803(95%CI: 0.460-0.951) | 0.983(95%CI: 0.924- 0.996) |
| Asia | ||||
| 10 | 11 | 1903 | 0.603(95%CI: 0.488- 0.707) | 0.886(95%CI: 0.772- 0.947) |
| 12.5 | 9 | 1527 | 0.594(95%CI: 0.474- 0.704) | 0.861(95%CI: 0.718- 0.938) |
| 15 | 8 | 1353 | 0.564(95%CI: 0.442- 0.678) | 0.881(95%CI: 0.731- 0.953) |
| 20 | 5 | 772 | 0.527(95%CI: 0.345- 0.701) | 0.938(95%CI: 0.750- 0.987) |
| ELISA | ||||
| 10 | 12 | 3098 | 0.759(95%CI: 0.653- 0.840) | 0.901(95%CI: 0.831- 0.944) |
| 12.5 | 11 | 2883 | 0.765(95%CI: 0.644- 0.855) | 0.895(95%CI: 0.816- 0.942) |
| 15 | 9 | 2465 | 0.769(95%CI: 0.603- 0.879) | 0.912(95%CI: 0.837- 0.955) |
| 20 | 6 | 1785 | 0.783(95%CI: 0.484- 0.933) | 0.925(95%CI: 0.788- 0.976) |
| 25 | 3 | 1455 | 0.754(95%CI: 0.703- 0.800) | 0.928(95%CI: 0.911- 0.942) |
| RIA | ||||
| 10 | 13 | 3641 | 0.628(95%CI: 0.521- 0.725) | 0.953(95%CI: 0.906- 0.977) |
| 12.5 | 9 | 2741 | 0.592(95%CI: 0.459- 0.712) | 0.966(95%CI: 0.907- 0.988) |
| 15 | 7 | 2049 | 0.542(95%CI: 0.390- 0.687) | 0.978(95%CI: 0.925- 0.994) |
| 20 | 5 | 1591 | 0.504(95%CI: 0.311- 0.696) | 0.988(95%CI: 0.941- 0.998) |
| 25 | 3 | 1295 | 0.438(95%CI: 0.395- 0.482) | 0.992(95%CI: 0.983- 0.997) |
| ECISA | ||||
| 10 | 4 | 1584 | 0.700(95%CI: 0.643- 0.753) | 0.847(95%CI: 0.826- 0.866) |
| 12.5 | 4 | 1584 | 0.700(95%CI: 0.643- 0.753) | 0.847(95%CI: 0.826- 0.866) |
| 15 | 4 | 1584 | 0.700(95%CI: 0.643- 0.753) | 0.847(95%CI: 0.826- 0.866) |
Two studies did not report the cut-off positive value of NSE; the cut-off value greater than or equal to 25 ng/ml were only found in one study, so this subgroup analysis could not conducted in Asian; ELISA: enzyme linked immunosorbent assay; ECSIA: electro- chemiluminescence immunoassay; RIA= radioimmunoassay assay. As for ECISA, when cut-off value was 20 ng/ml, only one studies was involved.