Finn chamber patch test technique

Proper technique aids reliable patch test results. The Finn chamber volume was determined to be 25 microliters. These studies suggest the optimal volume semi-solid test substance to be 12-15 microliters. More than 18-21 microliters caused significant extrusion of test substance and improper adhesive adherence. Finn chamber paper discs used with solutions absorb a maximum of 17.5 microliters test solutions and keep 15 microliters within the chamber. The evaporation rate of aqueous test solutions from Finn chambers was 1 mg/3 min; thus, the chambers should be applied quickly to avoid drying.