Abstract
Primary ciliary dyskinesia (PCD) symptoms are non-specific and tools to aid patient selection for referral are needed.
Objectives: To assess accuracy of a validated symptom score (PICADAR) [Behan, ERJ, 2016], in combination with nasal nitric oxide (nNO) to identify patients needing full diagnostics.
Methods: Prospective data from 142 consecutive referrals for PCD diagnostics (33 PCD positive, 111 negative). Sensitivity/specifity calculated using either PICADAR score >5 or nNO below threshold (30, 77 or 100nl/min) as a positive test compared to final diagnosis of PCD.
Results: PICADAR alone had sensitivity 0.88 and specificity 0.95. nNO+PICADAR improved identification of PCD positive patients. Accuracy was dependent on nNO threshold; sensitivities/specificities were 0.94/0.89, 0.94/0.78 and 1.0/0.73 using 30, 77 and 100nl/min.
| Accuracy of single test (nNO or PICADAR) | Accuracy of simultaneous testing (nNO or PICADAR positive) | ||||||
| nNO (30nl/min) | nNo (77nl/min) | nNo (100nl/min) | PICADAR | nNO (30nl/min) + PICADAR | nNO (77nl/min) + PICADAR | nNO (100nl/min) + PICADAR | |
| True pos | 30 | 31 | 33 | 29 | 31 | 31 | 33 |
| True neg | 105 | 91 | 81 | 105 | 99 | 86 | 78 |
| False pos | 6 | 20 | 30 | 6 | 12 | 25 | 33 |
| False neg | 3 | 2 | 0 | 4 | 2 | 2 | 0 |
| Sens.(95% CI) | 0.91 (0.76-0.98) | 0.94 (0.80-0.99) | 1.00 (0.89-1.00) | 0.88 (0.72-0.97) | 0.94 (0.80-0.99) | 0.94 (0.80-0.99) | 1.00 (0.89-1.0) |
| Spec.(95% CI) | 0.95 (0.89-0.98) | 0.82 (0.74-0.89) | 0.73 (0.64-0.81) | 0.95 (0.89-0.98) | 0.89 (0.82-0.94) | 0.78 (0.69-0.85) | 0.70 (0.60-0.79) |
Accuracy of individual/combination testing using PICADAR and nasal nitric oxide (nNO)
Conclusion: PICADAR effectively selects patients for referral to PCD diagnostics but some cases are missed. Addition of nNO provides a highly sensitive patient selection; 100nl/min nNO threshold gives a sensitivity and negative predictive value of 100%.
- Copyright ©the authors 2016
