Comparison of quantitative ELISA and semiquantitative Dustscreen for determination of Der p 1, Der f 1, and Fel d 1 in domestic dust samples.
BACKGROUND
Quantitative ELISA kits used for the measurement of indoor allergens are time-consuming. Therefore, an immunodot assay (Dustscreen) has been introduced, so that results can be obtained within 4 h. In order to assess the potential applications of the new method, we compared quantitative ELISA methods and Dustscreen.


METHODS
We compared the measurements of the mite allergens Der p 1 and Der f 1, and Fel d 1 by both Dustscreen and one brand of ELISA in 82 dust samples, and we also compared the measurement of the cat allergen Fel d 1 by Dustscreen and a different brand of ELISA in 77 dust samples. Optimum dilutions of dust extracts were compared between the ELISA and the immunodot assay. The nonparametric coefficient of correlation (Spearman's rank) was calculated for each allergen.


RESULTS
The immunodot assay was easy to perform. There was a good correlation between the results of the ELISA and Dustscreen (Der p 1: r=0.98, Der f 1: r=0.93, and Fel d 1: r=0.98). However, the coefficient of variation varied between 50% and 100% for Fel d 1 above 100 000 ng/g in Dustscreen. No cockroach allergen (Bla g 2) was detected in domestic dust samples in Berlin, and lower concentrations of group 2 allergen of mite (from not detectable to 19 500 ng/gm; median concentration 2000 ng/g) were found than mite group 1 allergens (sum of Der p 1 plus Der f 1: median 12 350 ng/g, minimum n.d., maximum 153 120 ng/g).


CONCLUSIONS
Our results indicate that quantification of indoor allergens in house-dust samples can be performed easily with Dustscreen, and both the technology and methodology are satisfactory.
Lau
S
S
University Children's Hospital Charité, Humboldt University, Berlin, Germany.
Schulz
G
G
Sommerfeld
C
C
Wahn
U
U
D000485:Allergens / Q000032:analysis*; D000911:Antibodies, Monoclonal; D039741:Antigens, Dermatophagoides; D004391:Dust / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006023:Glycoproteins / Q000032:analysis*; D007118:Immunoassay
D000485:Allergens; D000911:Antibodies, Monoclonal; D039741:Antigens, Dermatophagoides; D004391:Dust; D006023:Glycoproteins; C059296:Fel d 1 protein, Felis domesticus