Introduction: Primary ciliary dyskinesia (PCD) is a heterogeneous inherited ciliopathy in which respiratory cilia beat abnormally. Ciliary videomicroscopy using digital high-speed videomicroscopy (DHSV) allows to evaluate ciliary beating. However, the accurate ability of DHSV to diagnose PCD is difficult to define, as previous evaluations used a non-optimal reference standard, and as laboratories used different recording temperatures, which may influence ciliary beating.
 
Aims: To determine the ability of DHSV performed at room temperature (RT) or at 37° to diagnose PCD, using a complete reference standard which do not include DHSV.
 
Material and methods: Beating cilia were recorded using DHSV at 37°C and at RT, using nasal brushings from 54 patients referred for PCD diagnostic, and from 14 healthy subjects. Ciliary beating was assessed by ciliary beat frequency (CBF) and by the percentage of abnormal beat pattern (CBP). The reference standard used for PCD diagnosis was a diagnostic algorithm based on a panel of different tests, without including DHSV using fresh ciliated samples. The sensitivity and specificity of DHSV, performed at RT or at 37°C, were determined using the ROC curve and the area under the curve (AUC).
 
Results: According to the diagnostic algorithm, 15/54 referred patients were classified ?PCD?, 19/54 ?non-PCD?, and 20/54 ?inconclusive?. CBF and the percentage of abnormal CBP, measured at RT and at 37°C, were good parameters to discriminate PCD from non-PCD patients, as all AUC were > 0.7.

Conclusions: Our results suggest that both CBF and CBP are efficient to diagnose PCD, regardless of the temperature used to perform DHSV (at RT or at 37°C).