Routine diagnostic patch-testing with formaldehyde 2.0% (0.6 mg/cm2) may be an advantage compared to 1.0%.
Our clinical experience has suggested that the presently recommended patch-test concentration (1.0%) for formaldehyde in the baseline series might be too low. Therefore, consecutively patch-tested dermatitis patients were tested simultaneously with formaldehyde 1.0% and 2.0% (w/v) in aqua. Formaldehyde 1.0% and 2.0% were applied with a micro-pipette (15 microl) to filter paper discs in Finn Chambe