Which test chambers should be used for acetone, ethanol, and water solutions when patch testing?

For solutions, there is a generally accepted amount to be applied in a Finn Chamber and van der Bend chamber, that is, 15 and 20 microl, respectively. The objective of this study was to determine if the recommended volume is adequate. 12 volunteers were patch tested with green-coloured solutions of water, ethanol, and acetone in the Finn and van der Bend chambers on the back on 2 occasions. On D2 test sites were scored. A negative test equalled a test area not covered to 100%. A positive test meant a completely green-coloured test area. Minor and major spreading was noted. The appropriate amount equalled at the most 5% negative reactions. Major spreading was to be minimized to 5%. For ethanol, 100% positive reactions were noted in both test systems. Major spreading was seen in 23/24 Finn Chambers. No spreading (major or minor) was noted for van der Bend chambers with any of the 3 solutions. With acetone and water, negative reactions in 0-8% were noted both with Finn Chambers and van der Bend chambers. To conclude, water solutions should preferably be tested in Finn Chambers, while ethanol and acetone solutions are better tested in van der Bend chambers.