Table 1.
The effect of an imperfect gold standard on the sensitivity and specificity of a new biomarker that is in fact 100% sensitive and specific for acute kidney injury.
| True AKI (i.e., tubular injury) | |||
|---|---|---|---|
| AKI | No AKI | Total | |
| AKI according to SCr | 180 | 80 | 260 |
| No AKI according to SCr | 20 | 720 | 740 |
| Total | 200 | 800 | 1000 |
| sensitivity = 90% | specificity = 90% | ||
| AKI according to SCr | |||
|---|---|---|---|
| AKI | No AKI | Total | |
| New biomarker positive | 180 | 20 | 200 |
| New biomarker negative | 80 | 720 | 800 |
| Total | 260 | 740 | 1000 |
| apparent sensitivity = 69% | apparent specificity = 97% | ||
Abbreviations: SCr, serum creatinine; AKI, acute kidney injury