Wipe test for the detection of indoor allergens

BACKGROUND: The determination of house dust mite and cat allergens is a prerequisite for qualified assessment of exposure risk indoors. We describe the validation of integrated wipe tests comprising a porous sampling pin for the collection of settled house dust and an immunochemical test set-up for specific analysis of dust associated allergens. METHODS: Wipe tests comprised an immunochromatographic test system and a porous sampling pin for collecting dust by manually wiping a surface. Two different wipe tests were developed with specificity to cat allergen (Fel d 1) and to dust mite allergen (Der p 2/f 2). One-hundred and fifty on-site determinations for each of the allergens in 50 different households completed the field study to validate the analytical system. Reference analysis was based on collection of dust with a vacuum cleaner and analysis of dust associated allergens by ELISA. RESULTS: The wipe tests were found to produce semiquantitative results (class 0-3) on-site within 10 min of analysis time. For dust mite (cat) allergen the median of class 0-3 was 119 (263), 812 (844), 2708 (5670) and 8000 (56 800) ng/g dust, respectively. With respect to cut-off levels for dust mite (cat) allergens the clinical sensitivity was 62% (79%) and the clinical specificity was 94% (92%). CONCLUSIONS: The wipe tests proved to be a reliable tool for indoor allergen exposure screening, suitable for use even by untrained persons. This may have an impact on compliance with allergen avoidance measures.