Table 2 Methods and limitations used for confirmation of PCD diagnosis
From: Diagnosis and management of primary ciliary dyskinesia
| Method | Limitation |
|---|---|
| Nasal NO level | May be decreased in other disorders, for example, acute sinusitis or cystic fibrosis; rarely normal values may be present in PCD |
| High frequency video microscopy (HVMA) | Variants with subtle beating abnormality may be interpreted as normal; secondary ciliary dyskinesia due to infection and inflammation is very common - distinction from PCD phenotype may be difficult |
| Transmission electron microscopy (TEM) | Approximately ~30% of PCD cases have no ultrastructural abnormality; false-positive diagnoses common in some variants (notably inner dynein arm defects) |
| Immunofluorescence microscopy (IF) | No abnormality in approximately ~20%; technical difficulties if specimen contains a lot of mucus |
| Genetics | Expensive due to high number of PCD genes; only approximately 60% of cases can be identified by genetic testing at present |