Table 2 Accuracy of Gram stain in predicting Staphylococcus aureus in the tracheal aspirate
Sensitivity | 68.4 |
Specificity | 97.8 |
Positive Predictive Value | 88.1 |
Negative Predictive Value | 92.8 |
Positive Likelihood Ratio | 31.1 |
Negative Likelihood Ratio | 0.3 |
Pre-Test Probability | 19.4 |
Post-Test Probability – Positive | 88.2 |
Post-Test Probability - Negative | 7.2 |