Quantitative evaluation of passive cutaneous anaphylaxis (PCA) using a hand-held spectrophotometer.

A hand-held spectrophotometer was used for the quantitative evaluation of PCA caused by anti-TNP-IgE and TNP-BSA. A good relationship existed between the dilution of sera and the value of delta E*ab (a numerical expression of color) obtained by a hand-held spectrophotometer. In addition, the value of delta E*ab and the amount of Evans blue measured by the conventional colorimetric method correlated well. Because the method using a hand-held spectrophotometer provides a simple and objective analysis, it appears that the method is suitable as a substitute for the conventional method, which is time-consuming and requires killing animals cruelly.