The use of dextran-coated activated charcoal (DCC) powder to absorb solubilising detergents from cell lysates is described. Normal embryonic epithelial cells were lysed in the presence of sodium dodecyl sulphate (SDS). The detergent was then absorbed with DCC to facilitate analysis of polycystin-1 with antibody-based methods. Polycystin-1 is a membrane protein that is involved in the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD). The adverse effect of SDS on antibody-polycystin-1 binding was studied and the improvement resulting from its removal demonstrated using enzyme-linked immunosorbent assays (ELISAs). The results indicate that DCC can be used in a simple manner to remove highly reactive membrane-solubilising reagents from protein mixtures prior to immunological analysis. This procedure may be relevant to a variety of other techniques that are normally affected by detergents.