Comparison between the Acarex R test and a Der p 1 ELISA for the detection of house-dust mites in the homes of asthma sufferers.

Exposure to house-dust mite allergens in early childhood is an important determinant of the subsequent development of asthma. The Acarex R semi-quantitative test (Noristan) is marketed for use in patients' homes to assess mite levels in house dust. In order to evaluate the reliability of the test in a coastal area where house-dust mites are known to be prevalent, house-dust mite levels were estimated in 119 dust samples obtained from the homes of asthmatic children in a comparative study, by means of the Acarex R test and a Der p 1 enzyme-linked immunosorbent assay (ELISA). A linear regression of the 4 Acarex classes against log Der p 1 revealed a significant correlation (P = 0,0001) but there was a poor correlation between low Acarex R scores and the Der p 1 allergen levels determined by ELISA. Acarex R scores of 2 and 3 were usually associated with Der p 1 levels greater than 10 micrograms/g dust. Our studies indicate that the Acarex R test will identify high levels of mite allergens. Although its application may be limited in coastal areas such as the Cape Peninsula, it may be more useful inland, in climates where house-dust mites are not commonly encountered in all homes.