Cut off points of sialometrical and sialochemical variables for a positive diagnosis of SS. Variables are ranked by likelihood ratio
| Test variable | Cut off point | Specificity | Sensitivity | LR | PPV | NPV |
|---|---|---|---|---|---|---|
| *Restricted cut off point, with highest specificity; †widened cut off point, with increased sensitivity and decreased specificity. | ||||||
| LR, likelihood ratio; PPV, positive predictive value; NPV, negative predictive value; SM/SL, submandibular/sublingual. | ||||||
| Sialometry | ||||||
| Stimulated SM/SL flow* | <0.05 ml/min | 1.00 | 0.38 | ∞ | 1.00 | 0.55 |
| Parotid lag phase | >2.20 min | 0.93 | 0.42 | 6 | 0.89 | 0.54 |
| Unstimulated SM/SL flow | ≤0.01 ml/min | 0.76 | 0.67 | 3 | 0.78 | 0.64 |
| Stimulated SM/SL flow† | ≤0.20 ml/min | 0.76 | 0.62 | 3 | 0.77 | 0.60 |
| Sialochemistry (stimulated) | ||||||
| Parotid sodium* | ≥20 mmol/l | 1.00 | 0.48 | ∞ | 1.00 | 0.62 |
| Parotid sodium† | ≥10 mmol/l | 0.95 | 0.71 | 14 | 0.94 | 0.74 |
| Parotid chloride | ≥30 mmol/l | 0.93 | 0.46 | 7 | 0.87 | 0.64 |
| SM/SL chloride | >20 mmol/l | 0.90 | 0.57 | 6 | 0.80 | 0.76 |
| SM/SL sodium | >10 mmol/l | 0.85 | 0.63 | 4 | 0.82 | 0.69 |
| SM/SL phosphate | ≤2.50 mmol/l | 0.85 | 0.55 | 4 | 0.73 | 0.73 |
| Parotid phosphate | ≤4.75 mmol/l | 0.71 | 0.67 | 2 | 0.72 | 0.66 |