Table 1 Reliability and limitations of diagnostic methods in NPC
Diagnostic method | Sensitivity | Specificity | Comment |
|---|---|---|---|
Clinical evaluation | Low-to-moderate | Usually low | Depends on the form and stage of disease and experience of clinician |
Histology, histochemistry and electron microscopy of appropriate tissues (bone marrow smear, spleen, liver, brain) | Not exactly defined, in particular tissue probably moderate, at autopsy moderate-to-high | High | Must be performed by experienced histopathologist* |
Filipin staining test (alone or in combination with LDL-cholesterol assay) | High (but not absolute) | High (but not absolute) | Must be performed by experienced laboratory. Less reliable in persons with “variant biochemical subtype”. Similar results in some other IEM**. |
Molecular genetic analysis | High (but not absolute) | High (but not absolute) | Only one mutation identified in some patients; difficult decision regarding pathogenicity of novel private mutations in NPC genes |