For samples up to 4 x 15 x 15 mm fixed in a standard tissue cassette, incubate tissue specimen(s) at room temperature (15–25°C) for a minimum of 2 hours, but preferably 3–24 hours. For samples up to 20 x 20 x 20 mm fixed in the PAXgene Tissue FIX Container (50 ml), incubate for 6–48 hours, but preferably 8–24 hours. For biopsies with a thickness of 1 mm or less, fixation time can be reduced to 1 hour. Prolonged fixation times of up to 120 hours (e.g. over the weekend) is possible. Please note that fixation longer than the indicated times may lead to degradation of biomolecules.