PAS-Alcian Blue technique is used to differentiate between acidic mucins as sialomucins, sulfomucin and neutral epithelial mucin. After staining, acidic mucins will be coloured blue, neutral in magenta and nuclei in deep blue. Mixtures of acidic and neutral mucins give blue/ purple colour.Uses and sample preparation:Slides should be deparaffinized through xylene or substitute and descending grades of alcohol to distilled water prior to staining.Components:Schiff ReagentPeriodic acid 0,5%Harris HematoxylinAlcian BlueShort procedure:Place in Alcian BlueWash in running tap water and distilled waterPlace in periodic acid 0.5%Rinse with running tap water and distilled waterApply Schiff’s ReagentRinse with running tap water and distilled waterApply HematoxylinRinse with tap waterDehydrate with graded ethanol, clear and coverStaining characteristics:Acidic mucins can be coloured in blue, neutral in magenta and nuclei in deep blue. Mixtures of acidic and neutral mucins give blue/ purple color.