Table 2. Quality assessment of 27 studies by QUADAS-2.
| Study | Risk of bias | Applicability concerns | |||||
|---|---|---|---|---|---|---|---|
| Patient selection | Index test | Reference standard | Flow and timing | Patient selection | Index test | Reference standard | |
| Lam D | L | UC | L | L | L | L | L |
| Uchida J | L | L | L | L | L | L | L |
| Karachaliou N | L | L | L | L | L | L | L |
| Mok T | L | UC | L | L | L | L | L |
| Zhu G | L | H | L | L | L | L | L |
| Douillard J | L | L | L | L | L | L | L |
| Couraud S | L | L | L | L | L | L | L |
| Weber B | L | UC | L | L | L | L | L |
| Li X (plasma) | L | L | L | L | L | L | L |
| Li X (serum) | L | L | L | L | L | L | L |
| Wang S | L | UC | L | L | L | L | L |
| Jing C | L | L | L | L | L | L | L |
| Kim HR | L | L | L | L | L | L | L |
| Kim ST | L | L | L | L | L | L | L |
| Zhang H | L | L | UC | L | L | L | L |
| Liu X | L | L | L | L | L | L | L |
| Hu C | L | L | UC | L | L | L | L |
| Zhao X | L | L | UC | L | L | L | L |
| Goto K | L | L | UC | L | L | L | L |
| Xu F | L | L | L | L | L | L | L |
| Huang Z | L | UC | L | L | L | L | L |
| Jiang B | L | L | L | L | L | L | L |
| Sriram K | L | H | L | L | L | L | L |
| He C | L | H | L | L | L | L | L |
| Bai H | L | L | L | L | L | L | L |
| Kuang Y | L | UC | L | L | L | L | L |
| Kimura H | L | H | L | L | L | L | L |
L: Low H: High UC: Unclear.