Abstract: Leucocytes can be quickly and selectively separated from erythrocytes by subjecting a whole blood sample to a series of steps including lysing the erythrocytes and washing the remaining leucocytes with a solution containing ammonium chloride and a carboxylic acid or a metal carboxylate. The resulting white blood cells can be readily lysed and subjected to polymerase chain reaction to amplify and detect a target nucleic acid. The test kit useful in practicing the amplification method includes a labeled primer, a PCR reagent and a reagent mixture containing ammonium chloride and a carboxylic acid or a metal carboxylate for sample preparation.

Abstract: Nucleic acids can be made available for amplification or other treatment after lysis by contacting the lysate with polyethyleneimine to form a precipitate with the nucleic acids. The nucleic acids are then released from the precipitate by contact with a strong base, and the released nucleic acids are kept in solution with an anionic phosphate ester surfactant. This method for preparing specimen samples is simple and quite rapid.

Abstract: Nucleic acids can be made available for amplification or other treatment after lysis by contacting the lysate with specific weakly basic polymers to form a precipitate with the nucleic acids at acidic pH. After removing non-precipitated materials, the pH is then made basic, thereby releasing the nucleic acids from the polymer. This method for preparing specimen samples is simple and quite rapid, and the released nucleic acids can be further treated in hybridization assays or amplification procedures. The weakly basic polymers are water-soluble and cationic at acidic pH, but neutral in charge at basic pH.

Abstract: Weakly basic ethylenically unsaturated polymerizable monomers and polymers have been prepared. The monomers are represented by the structure (I): ##STR1## wherein R is hydrogen or methyl, and R.sup.1 is alkylene of 1 to 3 carbon atoms. The resulting polymers are water-soluble and cationic at acidic pH, but water-insoluble and neutral in charge at basic pH. The polymers are useful for precipitating nucleic acids.

Abstract: Weakly basic ethylenically unsaturated polymerizable monomers and polymers have been prepared. The monomers are represented by the structure (I): ##STR1## wherein R is hydrogen or methyl, and R.sup.1 is alkylene of 1 to 3 carbon atoms. The resulting polymers are water-soluble and cationic at acidic pH, but water-insoluble and neutral in charge at basic pH. The polymers are useful for precipitating nucleic acids.