Table 4.
Diagnostic performance of each test in terms of sensitivity, specificity, PPV (Positive Predictive Value) and NPV (Negative Predictive Value) which were determined from the final diagnosis of SFN based per se on the abnormality of two tests.
| Total population | Definite SFN | Possible SFN | No SFN | Sensitivity | Specificity | PPV | NPV | |
|---|---|---|---|---|---|---|---|---|
| (CI 95%) | (CI 95%) | |||||||
| Total | 245 | 102 | 53 | 90 | ||||
| Skin biopsy | ||||||||
| Normal | 155 | 42 | 33 | 80 | 0.58 | 0.91 | 0.88 | 0.66 |
| Abnormal | 84 | 59 | 17 | 8 | (0.48–0.68) | (0.83–0.96) | ||
| QST | ||||||||
| Normal | 87 | 28 | 24 | 35 | 0.72 | 0.39 | 0.57 | 0.55 |
| Abnormal | 155 | 72 | 29 | 54 | (0.62–0.81) | (0.29–0.50) | ||
| Q-Sweat | ||||||||
| Normal | 131 | 44 | 28 | 59 | 0.53 | 0.69 | 0.65 | 0.58 |
| Abnormal | 97 | 50 | 20 | 27 | (0.43–0.64) | (0.58–0.78) | ||
| ESC study | ||||||||
| Normal | 145 | 40 | 26 | 79 | 0.60 | 0.89 | 0.86 | 0.66 |
| Abnormal | 97 | 61 | 26 | 10 | (0.50–0.70) | (0.80–0.94) | ||
| LEP | ||||||||
| Normal | 135 | 32 | 32 | 71 | 0.66 | 0.89 | 0.88 | 0.68 |
| Abnormal | 86 | 63 | 15 | 8 | (0.56–0.76) | (0.80–0.94) | ||
| CVT | ||||||||
| Normal | 214 | 84 | 45 | 85 | 0.15 | 0.96 | 0.81 | 0.50 |
| Abnormal | 27 | 15 | 8 | 4 | (0.09–0.24) | (0.89–0.99) | ||
SFN, Small Fiber Neuropathy; QST, Quantitative Sensory Testing; ESC, Electrochemical Skin Conductance; LEP, Laser Evoked Potentials; CVT, Cardio-Vascular Testing.