A side-by-side comparison of sampling methods for settled, indoor allergens

Abstract

Exposure to indoor allergens is associated with asthma, but there is no standardized sampling method for measuring allergens. We compared the association of measured allergen exposure and serum-specific IgE levels and the precision of three sampling methods (Cyclone, Mighty Mite, and Readivac II) to identify a standardized sampling method for indoor allergens. A random sample of 72 children, 5 to 17 years old, with doctor-diagnosed asthma who lived in the same residence >or=2 years were enrolled. Composite, side by side floor samples were obtained with all three methods. Dust allergen concentrations and serum-specific IgE levels were measured for Der f I, Fel d I, and Bla g I. Mean allergen concentration did not differ significantly by sampling method. Cat allergen was significantly correlated with serum-specific IgE for Cyclone (P=0.003) and Mighty Mite (P=0.008), but only marginally for Readivac II (P=0.07). Dust mite allergen was significantly correlated with serum-specific IgE for Readivac II (P=0.02) and Cyclone (P=0.038), but not for Mighty Mite (P=0.12). Cockroach allergen was not correlated with serum-specific IgE for any sampling method. In multiple linear regression, cat allergen was associated with serum-specific IgE for Cyclone (P=0.007) and Mighty Mite (P=0.02), but not for Readivac II (P=0.06). In contrast, dust mite allergen was marginally associated with serum-specific IgE for Readivac II (P=0.07), but not for Mighty Mite (P=0.64) or Cyclone (P=0.27). The Cyclone and Mighty Mite were more precise than Readivac II for cat allergen, but there was no difference for dust mite allergen (P>0.05). No single method is superior for measurement of indoor allergens. In general, cat allergen collected with the Cyclone was a better predictor of serum-specific IgE levels to Fel d I, whereas dust mite allergen collected with the Readivac II was a better predictor of serum-specific IgE levels to Der f I.