Abstract: An improved method for determining the presence of an analyte in an oral fluid sample. A portion of the sample is mixed or contacted with a chromogenic substrate effective to produce a colored product upon reaction with .alpha.-amylase present in the sample. After a selected reaction time, the reaction mixture is inspected to determine the level of such colored product produced. Production of a level of colored product above a selected threshold within the reaction time indicates that an effective volume of undiluted oral fluid sample has been collected which is sufficient to allow detection of the analyte. A device for use in the method is also disclosed.

Abstract: This invention relates to safe and effective methods for the extraction of nucleic acids. In particular, methods are described for isolating nucleic acid from a sample containing a biological mixture of nucleic acids and other biological compounds wherein the sample is combined with an extraction solution containing at least one organic compound such as benzyl alcohol or a benzyl alcohol derivative to form an aqueous and non-aqueous phase. The nucleic acid is isolated from the aqueous phase. Preferably, the resulting combined solution also contains bentonite, as defined below. Typically, the sample will first be combined with a lysing agent before extraction. The lysing agents preferred are chaotropic salts such as guanidinium hydrochloride and guanidinium isothiocyanate.

Abstract: This invention relates to safe and effective methods for the extraction of nucleic acids. In particular, methods are described for isolating nucleic acid from a sample containing a biological mixture of nucleic acids and other biological compounds wherein the sample is combined with an extraction solution containing at least one organic compound such as benzyl alcohol or a benzyl alcohol derivative to form an aqueous and non-aqueous phase. The nucleic acid is isolated from the aqueous phase. Preferably, the resulting combined solution also contains bentonite, as defined below. Typically, the sample will first be combined with a lysing agent before extraction. The lysing agents preferred are chaotropic salts such as guanidinium hydrochloride and guanidinium isothiocyanate.

Abstract: This invention relates to novel methods for the extraction of nucleic acid. In particular methods are described for isolating nucleic acid from a sample containing a complex biological mixture of nucleic acid and non-nucleic acids wherein the sample is combined with an extraction solution comprising a lactam and then the nucleic acid material is isolated from the resulting combined solution. The resulting combined solution is mixed and becomes biphasic and the nucleic acid material is isolated from the aqueous phase by precipitation with ethanol. The lactam is preferably about 5 to about 70% of the extraction solution and is most preferably 2-pyrrolidone, N-ethyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-dodecyl-2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, N-methyl-2-piperidone, 2-.epsilon.-caprolactam, N-methyl-2-caprolactam, 2-piperidone or N-(4-hydroxybenzyl)pyrrolidone. Methods for selectively isolating DNA, ribosomal RNA and plasmid DNA are also disclosed.