Dermatophagoides farinae allergen levels from two different sources within the same home: evaluation of two different collection techniques

Abstract

The allergens produced by the dust mites of the Dermatophagoides genus are now recognized as one of the major allergens in house dust. Quantification of those allergens helps to evaluate the effectiveness of avoidance measures and specific treatments aimed at the reduction of the mites and their allergens. The present study was undertaken to compare the level of D. farinae allergen collected by a standard vacuum cleaner with a disposable bag and the level of allergen collected by a hand-held vacuum equipped with a special filter. Samples were obtained from the main living area of 18 homes of patients allergic to D. farinae. Using a hand-held vacuum especially equipped with a removable micropore filter, a 2-m2 area of carpet was vacuumed for two minutes and an identical sample was collected from the major upholstered piece of furniture in the room. A third sample was obtained with an upright vacuum fitted with a clean disposable bag. The dust collected was extracted in phosphate buffered saline and resultant extracts were assayed for D. farinae allergen content by microtiter plate RAST inhibition assay. Results from these assays showed a large interhome variability regardless of sampling technique, but intrahome sampling showed remarkable consistency. A linear regression analysis demonstrated all of the comparisons correlated at a probability level of P less than .05. We conclude that dust mite allergen levels collected in a disposable bag vacuum cleaner are reliable indicators of the level of house dust mites present in the homes of patients.