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Table 2 Overview of screening tests applied to diagnosis of fungi-associated conditions

From: Fungal allergy in asthma–state of the art and research needs

Test Strengths Weaknesses Comment
Skin prick test (SPT) Simple to perform. Rapid results. Good tolerability. Inexpensive. High negative predictive value (95%) Accuracy and reliability dependent on quality of fungal extracts. Variability between different batches of test. Test should be performed with standardised allergen solution, if possible. Best used in conjunction with sIGE due to discordance in results.
Misses low sensitivity responses.
Systemic and topical antihistamines may suppress weal and flare reaction. Presence of IgE without clinical symptoms.
Intradermal tests More sensitive than SPT. Higher rate of false positives than SPT. Rarely used.
IgE (ImmunoCAP)a Completely safe. Not influenced by concurrent drug treatment. Results not immediately available. Testing more expensive than SPT. Presence of IgE without clinical symptoms. Best used in conjunction with SPT due to discordance in results.
Complete blood count Automated test. Many different conditions result in increases or decreases in cell populations. Lack of correlation between peripheral blood eosinophil levels and lung function / immunological parameters. Performed to assess peripheral blood eosinophil levels.
Fungal culture of sputum Simple to perform. Inexpensive. Lack of standardisation in most countries. UK standard insensitive. Actively growing culture needed for strain-typing or anti-fungal sensitivity
Fungal PCR of sputum More sensitive than culture. May have high false-positives. Requires specialised equipment, although most labs have PCR machines. Commercial tests available but no accepted standard for positivity.
  1. a = often referred to as RAST tests, although the original radioallergoabsorbent test has been superceded by the ImmunoCAP or simpler ELISA tests.