[Evaluation of Petri dish sampling for assessment of airborne dust mite allergen in Japan].

ABSTRACT

BACKGROUND: Several allergen sampling methods are available for the assessment of personal or indirect exposure to indoor allergens. As an index of exposure to inhalant allergens, assays of the amount of airborne allergens directly reflect personal exposure. OBJECTIVE: We evaluated the Petri dish sampling method of assessing the level of airborne Dermatophagoides dust mite group 1 (Der 1) allergens. METHODS: We collected settling dust samples from one person's bedroom over a period of 2 years by using a Petri dish, adhesive tape, and a vacuumed reservoir. We also collected settling dust samples from the bedrooms of 42 asthma patients by using a Petri dish and adhesive tape. The amounts of Der 1 collected on the Petri dishes and adhesive tapes were measured by sensitive fluorometric ELISA. RESULTS: Der 1 was detected in all samples by using a Petri dish. The mean coefficient of variation was approximately 15%. We found that Petri dishes set at lower sampling heights contained more Der 1 than those higher up. There were also seasonal changes in the amounts of Der 1 collected, with the highest amounts collected from summer to autumn, and the lowest amounts collected in winter. CONCLUSION: The Petri dish sampling method for collecting settling Der 1 is very simple and can be used as an alternative to personal air sampling, especially in large-scale studies.