What does the Aspergillus niger-specific Immunoglobulin E test measure?

Why is Aspergillus niger-specific Immunoglobulin E measured?

Serum IgE to Aspergillus niger identifies IgE-mediated sensitivity in patients with suspected mould allergy, allergic rhinitis, allergic asthma, or allergic bronchopulmonary aspergillosis. A positive result does not establish clinical allergy by itself — sensitisation must correlate with history and symptoms. Elevated Aspergillus IgE is one element of the ABPA diagnostic criteria, though total IgE and A. fumigatus-specific IgE are typically more prominent. This test informs environmental remediation, helps distinguish sensitisation from active ABPA, and guides decisions about antifungal or immunomodulatory therapy.

Reference ranges

Standard reference

<0.10 kU/L (Class 0, undetectable). Class 1 (0.10–0.34) equivocal; Class 2–6 (≥0.35) positive with increasing likelihood of clinical sensitivity.

Functional medicine optimal

Class 0 (<0.10 kU/L) indicates no detectable sensitisation. Class 1 is equivocal and should be correlated with exposure history and symptoms; Class 2 and above carry progressively higher likelihood of clinical reactivity, though magnitude does not reliably predict symptom severity.

Units

kU/L, IU/mL

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.