Table 1

Diagnostic testing in primary cell dyskinesia (PCD)

TestInterpretationRole in PCD diagnosis
Saccharin test3False negatives and false positives, screening test at bestNot useful to diagnose or exclude PCD
Radionuclide mucociliary clearance4Good sensitivity and specificity but only limited experience or access in most centresNot useful to diagnose or exclude PCD
Nasal nitric oxide5Used as the screening test of choice, also low in cystic fibrosis and other conditions; now also part of the diagnostic investigationNormal nasal nitric oxide = PCD very unlikely
Ciliary motility studiesCan be affected by recent viral infection
  • Normal ciliary beat frequency and pattern = PCD excluded

  • If abnormal, repeat after treatment of infection or proceed to ciliary culture

  • Abnormal ciliary beat frequency and/or pattern on an adequate sample = definite PCD

Transmission electron microscopyCan be affected by recent viral infection
  • Presence of known disease producing structural abnormality = definite PCD

  • Can be normal with definite PCD

Culture of ciliary biopsy6Cilia regrown in culture, used to differentiate secondary ciliary dyskinesia in PCD
  • Normal ciliary beat frequency and pattern = PCD excluded

  • Abnormal ciliary beat frequency and/or pattern on an adequate sample = definite PCD

Genetic studies>250 potential loci, very few known genes
  • Two known disease producing mutations in trans = definite PCD

  • Can be no known mutations detected with definite PCD

Immunofluorescence of ciliary proteins7Limited experience only and applicable to date to very few proteins
  • Insufficient evidence to evaluate a role in clinical practice

  • Not a stand-alone diagnostic test