Objective:

To evaluate the diagnostic accuracy of nasal nitric oxide (nNO) measurement for primary ciliary dyskinesia (PCD) and its role in a multimodal diagnostic pathway, emphasizing its integration with other diagnostic methods.

Key Findings:

• nNO demonstrated a sensitivity of 98% and specificity of 96% across 12 studies with 1,344 patients, with noted variability in performance based on patient populations and measurement techniques.
• In referral populations, diagnostic performance was lower than in controlled settings, highlighting the need for context-specific interpretation.
• Sensitivity and specificity varied based on measurement techniques and patient populations, indicating the importance of tailored diagnostic approaches.
• Some patients with confirmed PCD had nNO values within the normal range, particularly those with specific genetic variants.
• Test performance was influenced by technical factors, patient cooperation, and clinical context, including the impact of respiratory infections.

Interpretation:

Nasal nitric oxide measurement is a valuable first-line assessment tool for PCD but should not be used in isolation due to variability in diagnostic performance across different patient groups and contexts, necessitating a comprehensive diagnostic approach.

Limitations:

• Variability in nNO levels based on genetic subtypes, age, and clinical context, which complicates the reliability of nNO as a universal diagnostic marker.
• Respiratory infections can significantly lower nNO values, complicating diagnosis and potentially leading to misinterpretation.
• Some patients with confirmed PCD may present normal nNO levels, underscoring the need for additional testing.

Conclusion:

Nasal nitric oxide measurement should be integrated into a comprehensive diagnostic approach for PCD, alongside other testing methods, due to its limitations as a standalone diagnostic marker and the variability observed in different patient contexts.

Sources:

• Pediatric Pulmonology