After drying, the area is dusted with cornstarch or potato flour.
Sweating is then encouraged by increased room temperature, exercise, use of a sauna, or pilocarpine.
[2] When sweat reaches the surface of the skin, the starch and iodine combine, causing a drastic color change (yellow to dark blue), allowing sweat production to be easily seen.
[2] Some have reported higher sensitivity and fewer drawbacks marking dry skin with water-erasable ink and observing fading.
[3] The Minor test can be used as a diagnostic tool to evaluate underactive (hypohidrosis)[4] and overactive (hyperhidrosis) sweating.