The HMT includes five repeated 48-hour occlusive patch tests on the same skin site with a 24
hour rest period between removal and reapplication of the patch. Substances with irritating
potential are applied in a concentration giving a moderate erythema and for substances that
are non-irritating the test site is pretreated with a 24-hour patch of 5% sodium lauryl sulphate
before induction. Following a two-week rest period after the last induction patch, the extent of
sensitisation is evaluated by a 48-hour occluded patch test with the maximum non-irritating
concentration of the substance on a slightly irritated skin site. The challenge site is scored
after 24 and 48 hours after patch removal and the sensitisation index is noted. Because the
human maximisation test may produce a rather dramatic effect on the skin it may be
considered unacceptable today.