House-dust mite allergen Der p 1: amount or concentration?

There is a lack of consensus as to the best way to quantify settled house-dust mite Der p 1 allergen from planar and nonplanar surfaces. To investigate the most appropriate measure of settled house-dust mite Der p 1 allergen, we determined the relationship between Der p 1 allergen content and collected dust weight from planar-surface (mattress) and nonplanar-surface (living-room) samples in 58 homes. There was a direct relationship between Der p 1 content and dust weight for both planar-surface (mattress, n = 217) samples (r = 0.50, P < 0.0001) and nonplanar-surface (living-room, n = 48) samples (r = 0.61, P < 0.0001). Correction for the surface area of the planar surface (mattress) vacuum-cleaned resulted in no additional benefit. We conclude that expression of Der p 1 levels per weight of collected dust appears to be the best method for both planar and nonplanar surfaces.