Diagnostic potential of sialometrical/sialochemical tests for SS, after stratifying for raised serum IgG (normal ≤15 g/l). Adjusted (widened) salivary cut off points are applied if serum IgG is raised in order to improve the sensitivity
| Criteria for classifying SS test (cut off point approach) | Specificity | Sensitivity | LR | No | PPV | NPV | ||
|---|---|---|---|---|---|---|---|---|
| LR, likelihood ratio; No, number of cases included in the analysis out of total (observation group n=100). Cases were rejected when data were missing in all variables used in the criteria; PPV, positive predictive value; NPV, negative predictive value; SM/SL, submandibular/sublingual. | ||||||||
| Sialometrical variables and IgG | ||||||||
| 15. | IgG ≤15: | Stimulated SM/SL flow <0.05 ml/min | ||||||
| IgG >15: | Stimulated SM/SL flow ≤0.20 ml/min | 0.95 | 0.53 | 11 | 100 | 0.94 | 0.61 | |
| Sialochemical variables and IgG | ||||||||
| 16. | IgG ≤15: | Parotid (stimulated) sodium ≥20 mmol/l | ||||||
| IgG >15: | Parotid (stimulated) sodium ≥10 mmol/l | 1.00 | 0.69 | ∞ | 90 | 1.00 | 0.74 | |
| Sialometrical/sialochemical variables and IgG | ||||||||
| 17. | IgG ≤15: | Parotid (stimulated) sodium ≥20 mmol/l or | ||||||
| Stimulated SM/SL flow <0.05 ml/min | ||||||||
| IgG >15: | Parotid (stimulated) sodium ≥10 mmol/l or | 0.95 | 0.83 | 17 | 100 | 0.96 | 0.80 | |
| Stimulated SM/SL flow ≤0.20 ml/min | ||||||||
| 18. | IgG ≤15: | Parotid (stimulated) sodium ≥20 mmol/l or | ||||||
| Parotid (stimulated) chloride ≥30 mmol/l or | ||||||||
| Stimulated SM/SL flow <0.05 ml/min | ||||||||
| IgG >15: | Parotid (stimulated) sodium ≥10 mmol/l or | 0.90 | 0.86 | 9 | 100 | 0.93 | 0.83 | |
| Parotid (stimulated) chloride ≥30 mmol/l or | ||||||||
| Stimulated SM/SL flow ≤0.20 ml/min | ||||||||
| 19. | IgG ≤15: | Parotid (stimulated) sodium ≥20 mmol/l or | ||||||
| Parotid (stimulated) chloride ≥30 mmol/l or | ||||||||
| Stimulated SM/SL flow <0.05 ml/min or | ||||||||
| Parotid lag phase >2.20 min | ||||||||
| IgG >15: | Parotid (stimulated) sodium ≥10 mmol/l or | 0.88 | 0.91 | 8 | 100 | 0.91 | 0.88 | |
| Parotid (stimulated) chloride ≥30 mmol/l or | ||||||||
| Stimulated SM/SL flow ≤0.20 ml/min or | ||||||||
| Parotid lag phase >2.20 min | ||||||||