Table 4.
Performance of cTn versus that of sTnI and hsTnI at each time point, for A) ACS (both acute MI and UAP) and B) UAP alone. Compared to cTn, the two more sensitive methods had greater sensitivity for acute MI at first drawn and substantially greater sensitivity for ACS at all time points. Additionally, hsTnI had 100% NPV at baseline to exclude all ACS.
| A) ACS (acute MI plus UAP) | |||||
|---|---|---|---|---|---|
| Operating characteristics: ACS | |||||
| Time point | Sens | Spec | PPV | NPV, 99th % | NPV, LOD |
| cTn, baseline (N=322) | 0% | 100% | N/A | 91% | N/A |
| cTn, second draw (N=252) | 14% | 100% | 100% | 93% | N/A |
| cTn, third draw (N=64) | 21% | 100% | 100% | 93% | N/A |
| sTnI, baseline (N=309) | 43% | 98% | 71% | 95% | 95% |
| sTnI, 90–155 minutes (N=289) | 46% | 98% | 69% | 95% | 95% |
| sTnI, 210–300 minutes (N=231) | 43% | 99% | 82% | 95% | 95% |
| hsTnI, baseline (N=309) | 43% | 97% | 60% | 95% | 100% |
| hsTnI, 90–155 minutes (N=289) | 46% | 97% | 58% | 95% | 100% |
| hsTnI, 210–300 minutes (N=231) | 43% | 98% | 64% | 95% | 86% |
| B) UAP (excluding acute MI) | |||||
|---|---|---|---|---|---|
| Operating characteristics: ACS | |||||
| Time point | Sens | Spec | PPV | NPV, 99th % | NPV, LOD |
| cTn, baseline (N=315) | 0% | 100% | N/A | 93% | N/A |
| cTn, second draw (N=245) | 0% | 100% | N/A | 93% | N/A |
| cTn, third draw (N=58) | 5% | 100% | 100% | 94% | N/A |
| sTnI, baseline (N=302) | 29% | 98% | 55% | 95% | 95% |
| sTnI, 90–155 minutes (N=282) | 29% | 98% | 50% | 96% | 95% |
| sTnI, 210–300 minutes (N=226) | 31% | 99% | 71% | 95% | 95% |
| hsTnI, baseline (N=302) | 29% | 97% | 43% | 95% | 100% |
| hsTnI, 90–155 minutes (N=282) | 29% | 97% | 39% | 96% | 100% |
| hsTnI, 210–300 minutes (N=226) | 31% | 98% | 50% | 95% | 86% |
*NPV for cTn is at the lowest cut-off providing 10% imprecision.
Sens denotes: sensitivity; Spec denotes: specificity; PPV denotes: positive predictive value; NPV denotes: negative predictive value; LOD denotes: limit of detection; N/A denotes: not applicable.