Ciliary Beat Frequency and Pattern: An Accessible Tool for the Screening of Primary Ciliary Dyskinesia

<b>Background/Objectives</b>: Primary ciliary dyskinesia (PCD) is a rare inherited disorder caused by dysfunction of motile cilia, leading to chronic respiratory disease. Diagnosis is challenging due to heterogeneous and non-specific clinical manifestations and the absence of a single definitive diagnostic test. Current diagnostic strategies rely on a combination of functional, ultrastructural, and genetic analyses. The objective of this study was to evaluate whether ciliary beat frequency (CBF), combined with ciliary beat pattern (CBP) assessment using digital high-speed video microscopy (DHSV), could serve as an effective first-line screening tool to identify patients requiring further diagnostic investigations. <b>Methods</b>: This single-center retrospective study included 65 patients (52 children and 13 adults) with clinical suspicion of PCD. Ciliary beat analysis was performed on nasal or bronchial samples using DHSV and Sisson-Ammons Video Analysis software. CBF and CBP were assessed and compared between patients with confirmed PCD and those in whom PCD was excluded based on transmission electron microscopy (TEM) and/or molecular genetic analysis. <b>Results</b>: Fifteen patients were diagnosed with PCD. Mean CBF was significantly lower in the PCD group compared with the non-PCD group (3.3 Hz vs. 8.1 Hz; <i>p</i> < 0.001). A CBF cut-off value of 5.25 Hz yielded a sensitivity of 78.6% and a specificity of 95.7%. Three patients with PCD had CBF values above this threshold; however, two of them exhibited abnormal CBP. Sample type, patient age, and the presence of airway pathogens did not significantly influence CBF measurements. <b>Conclusions</b>: CBF and CBP analysis using DHSV represents a useful first-line screening tool within a multifaceted diagnostic approach for PCD, allowing rapid identification of patients who should undergo further confirmatory testing.