Table 2. The accuracy of Scys at various blood sampling point-in-time and cut-off value.
| Study | Blood sampling point-in-time | Scys cutoff value | Test results | Sensitivity (%) | Specificity (%) | AUROC (95% CI) | |||
|---|---|---|---|---|---|---|---|---|---|
| TP | FP | FN | TN | ||||||
| Herget-Rosenthal S.21 | On day after kidney injury | ↑ ≥ 50% from baseline | 43 | 3 | 1 | 38 | 98 | 93 | 0.99(0.98, 1.00) |
| 24 h before kidney injury | ↑ ≥ 50% from baseline | 36 | 2 | 8 | 39 | 82 | 95 | 0.97(0.94, 0.99) | |
| 24 h before kidney injury | ↑ ≥ 50% from baseline | 24 | 2 | 20 | 39 | 55 | 95 | 0.82(0.71, 0.92) | |
| Ling Q.22 | Post-Tx d 1,4, &7 | 1.57 mg/L | 11 | 3 | 2 | 14 | 84.6 | 84.5 | 0.94(0.86, 0.98) |
| Kato K.28 | Before,1,2,3 days after catheterization | 1.2 mg/L | 17 | 10 | 1 | 59 | 94.7 | 84.8 | 0.93 |
| Liang X. L.23 | Postoperative d1 | ↑ ≥ 50% from baseline | 27 | 5 | 2 | 98 | 92 | 95 | 0.99(0.98, 1.01) |
| Haase-Fielitz A.29 | On ICU admission | 1.1 mg/L | 18 | 11 | 5 | 66 | 77 | 86 | 0.83(0.68, 0.98) |
| 24 h after CPB | 1.2 mg/L | 21 | 28 | 2 | 49 | 91 | 64 | 0.84(0.75, 0.93) | |
| Haase M.24 | 6 h after CPB | 1.1 mg/L | 34 | 18 | 12 | 36 | 74 | 67 | 0.76(0.61, 0.91) |
| Nejat M.25 | On ICU admission | 0.8 mg/L | 18 | 123 | 1 | 176 | 95 | 59 | 0.80(0.71, 0.88) |
| Briguori C.26 | 24 h after CM exposure | ↑ ≥ 10% from baseline | 34 | 53 | 0 | 323 | 100 | 85.9 | 0.92 |
| Soto K27 | On ED admission | 0.98 mg/L | 106 | 113 | 24 | 373 | 81.4 | 76.7 | 0.87(0.83, 0.90) |
| 6 h after ED admission | 0.98 mg/L | 106 | 112 | 24 | 374 | 81.6 | 77.0 | 0.87(0.83, 0.91) | |
| 12 h after ED admission | 0.98 mg/L | 106 | 104 | 24 | 382 | 81.6 | 78.5 | 0.88(0.84, 0.91) | |
| 24 h after ED admission | 0.98 mg/L | 103 | 109 | 27 | 377 | 79.5 | 77.5 | 0.86(0.82, 0.90) | |
| 48 h after ED admission | 0.98 mg/L | 105 | 97 | 25 | 389 | 81 | 80.1 | 0.87(0.83, 0.91) | |
| Torregrosa L.30 | 12 h after CAG | 0.8 mg/L | 11 | 18 | 1 | 59 | 89 | 76 | 0.87(0.68, 1.06) |
| 12 h after CS | 0.8 mg/L | 9 | 12 | 5 | 20 | 64 | 64 | 0.68(0.46, 0.88) | |
| Chen T. H.31 | On CCU admission | 1.8 mg/L | 33 | 10 | 10 | 97 | 77 | 91 | 0.90(0.83, 0.96) |
| Liu X. L.32 | On hospital admission | 475 ng/mL | 22 | 54 | 17 | 218 | 57.1 | 80.1 | 0.63(0.53, 0.73) |
| 24 h after CM administration | 503 ng/mL | 22 | 108 | 17 | 164 | 57.1 | 60.2 | 0.63(0.54, 0.72) | |
| Hsiao P. G.33 | On 24 h of AMI after PCI | 1364 mg/L | 12 | 11 | 5 | 68 | 69.2 | 85.9 | 0.864 |
| Kokkoris S.34 | On ICU admission | 1.04 mg/L | 22 | 12 | 14 | 52 | 61.1 | 81.2 | 0.75(0.65, 0.83) |
| Aydoğdu M.35 | Within first 24 h of ICU admission | 1.5 mg/L | 46 | 28 | 17 | 60 | 73 | 68 | 0.82 |
| Alharazy S. M.36 | At 24 h after CM exposure | 0.19 mg/L | 7 | 10 | 4 | 79 | 63.64 | 88.76 | 0.80(0.70, 0.87) |
| Wan Z. H.16 | On Center admission | 1.21 mg/L | 8 | 6 | 0 | 42 | 100 | 87.5 | 0.97(0.85, 1.00) |
| Padhy M.37 | 0 h of angioplasty procedure | 0.504 mg/L | 20 | 11 | 10 | 19 | 66 | 63 | 0.70 |
| 4 h of angioplasty procedure | 0.517 mg/L | 20 | 10 | 10 | 20 | 66.7 | 66.6 | 0.72 | |
| 24 h of angioplasty procedure | 0.994 mg/L | 30 | 1 | 0 | 29 | 100 | 96.7 | 1.00 | |
| 48 h of angioplasty procedure | 0.961 mg/L | 28 | 1 | 2 | 29 | 93.3 | 96.7 | 0.99 | |
| Ghonemy T. A.38 | 3 h after CS | 2.65 ng/dL | 9 | 9 | 8 | 24 | 54.7 | 72.7 | NR |
| 6 h after CS | 2.65 ng/dL | 13 | 8 | 4 | 25 | 75.2 | 75.8 | NR | |
| Yang H. T.39 | 12 h from admission | 0.70 mg/L | 22 | 21 | 9 | 38 | 70.4 | 65.2 | 0.75 |
| 24 h from admission | 0.75 mg/L | 16 | 23 | 15 | 36 | 50.0 | 61.8 | 0.73 | |
| Prowle J. R.40 | 4.5 h after CPB | 1.24 mg/L | 19 | 25 | 6 | 43 | 76.0 | 63.2 | 0.69(0.56, 0.82) |
| 24 h after CPB | 1.57 mg/L | 16 | 15 | 9 | 53 | 64.0 | 77.9 | 0.72(0.59, 0.85) | |
| Arun O.41 | At 1 h after CS | 0.76 mg/dL | 12 | 5 | 4 | 9 | 75 | 65 | 0.74 |
| At 12 h after CS | 0.98 mg/dL | 12 | 3 | 4 | 11 | 75 | 80 | 0.77 | |
| At 24 h after CS | 0.83 mg/dL | 15 | 3 | 1 | 11 | 93 | 79 | 0.79 | |
| At 48 h after CS | 0.73 mg/dL | 13 | 4 | 3 | 10 | 81 | 72 | 0.72 | |
| Tung Y. C.42 | On ED admission | 1.6 mg/L | 29 | 47 | 8 | 105 | 79 | 69 | 0.73(0.63, 0.81) |
| Yim H.18 | At 7 d after Burn | 0.75 mg/L | 31 | 14 | 9 | 43 | 76.3 | 75.4 | 0.81(0.71, 0.91) |
| At 14 d after Burn | 0.85 mg/L | 36 | 10 | 4 | 47 | 89.5 | 82.5 | 0.91(0.84, 0.97) | |
| Chen J. Z.43 | At 24 h after PNE | 0.98 mg/L | 20 | 16 | 8 | 45 | 71.4 | 73.8 | 0.79(0.70, 0.89) |
| At 48 h after PNE | 1.005 mg/L | 19 | 21 | 9 | 40 | 67.9 | 65.6 | 0.76(0.66, 0.86) | |
| Liu Y. J.17 | 0 h after CS | 0.965 mg/L | 14 | 4 | 5 | 12 | 73.7 | 75.0 | 0.74(0.57, 0.91) |
| 4 h after CS | 1.150 mg/L | 15 | 4 | 4 | 12 | 78.9 | 75.0 | 0.86(0.74, 0.98) | |
| 24 h after CS | 1.275 mg/L | 18 | 2 | 1 | 14 | 94.7 | 87.5 | 0.97(0.97, 1.02) | |
| 48 h after CS | 1.405 mg/L | 18 | 2 | 1 | 14 | 94.7 | 87.5 | 0.97(0.93, 1.02) | |
| 72 h after CS | 1.380 mg/L | 18 | 3 | 1 | 13 | 94.7 | 81.2 | 0.94(0.87, 1.02) | |
| Peng L.44 | 24 h after PCI | ↑ ≥ 15% from baseline | 10 | 10 | 19 | 157 | 34.48 | 94.01 | 0.66(0.55, 0.77) |
| 48 h after PCI | ↑ ≥ 15% from baseline | 12 | 12 | 17 | 155 | 41.38 | 92.86 | 0.78(0.70, 0.87) | |
| Gong M. M.45 | On ICU admission | 1.54 mg/L | 54 | 4 | 17 | 101 | 76.1 | 96.2 | 0.90(0.86, 0.95) |
| GaygIsIz U19 | within the first 24–48 h of ICU admission | 0.94 mg/L | 12 | 18 | 7 | 35 | 63 | 66 | 0.67 (0.53, 0.81) |
| Martensson J.20 | within 48 h of ICU admission | 1.1 mg/l | 12 | 17 | 9 | 55 | 55 | 76 | 0.67 (0.54-0.81) |
Abbreviations: AKI, acute kidney injury; AUROC, the area under the receiver operating characteristic curve; CAG, coronary angiography; CM, contrast medium; CPB, cardiopulmonary bypass; CS, cardiac surgery; DOR, diagnostic odds ratio; Scys, serum cystatin C; TP, true positive; FP, false positive; FN, false negative; TN, true negative; Tx, transplant; ICU, intensive care unit; ED, emergency department; PCI, percutaneous coronary intervention; PNE, Partial nephrectomy; NR, not reported.