Table 3.
Diagnostic efficiency of culture, mNGS and tNGS in PJI.
| Variable | Non-PJI (n = 21) | PJI (n = 43) | Sensitivity | p-valuea (VS. tNGS) | Specificity | p-valuea (VS. tNGS) | PPA | NPA | Youden’s index | PPV | NPV | LR+ | LR- |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| tNGS | 1 | 38 | 88.4% | N/A | 95.2% | N/A | 0.88 | 0.95 | 0.84 | 97.4% | 80% | 18.56 | 0.12 |
| Culture | 2 | 32 | 74.4% | 0.18 | 90.5% | >0.99 | 0.74 | 0.90 | 0.65 | 94.1% | 63.3% | 7.81 | 0.28 |
| mNGS | 1 | 40 | 93.0% | 0.73 | 95.2% | >0.99 | 0.93 | 0.95 | 0.88 | 97.6% | 87.0% | 19.53 | 0.07 |
| CRP (>10 mg/L) | 2 | 33 | 76.7% | 0.27 | 90.5% | >0.99 | 0.77 | 0.90 | 0.67 | 94.3% | 65.5% | 8.06 | 0.26 |
| ESR (>30 mm/h) | 9 | 36 | 83.7% | 0.74 | 57.1% | <0.01 | 0.84 | 0.57 | 0.41 | 80% | 63.2% | 1.95 | 0.28 |
| SF-WBC (>3,000 × 106/L) | 0 | 37 | 86.0% | >0.99 | 100% | N/A | 0.86 | 1 | 0.86 | 100% | 77.8% | N/A | 0.14 |
| SF-PMN% (>80%) | 2 | 31 | 72.1% | 0.12 | 90.5% | >0.99 | 0.72 | 0.90 | 0.63 | 93.9% | 61.3% | 7.57 | 0.31 |
| tNGS + Culture | 3 | 42 | 97.7% | 0.13 | 85.7% | 0.50 | 0.98 | 0.86 | 0.83 | 93.3% | 94.7% | 6.84 | 0.03 |
| mNGS + Culture | 3 | 42 | 97.7% | 0.29 | 85.7% | 0.63 | 0.98 | 0.86 | 0.83 | 93.3% | 94.7% | 6.84 | 0.03 |
Youden’ s index = sensitivity + specificity – 1; PJI, Prosthetic joint infection. PPA, Positive percent agreement. NPA, Negative percent agreement. LR+, Positive likelihood ratio; LR−, Negative likelihood ratio; NPV, Negative predictive value; PPV, Positive predictive value; mNGS, metagenomic next-generation sequencing; tNGS, targeted next-generation sequencing.
a
McNemar’s test.