Abstract: Nucleic acid components in a biological sample are detected and/or quantified utilizing a process wherein the sample is first solubilized with a chaotropic salt solution. In a preferred embodiment, cells and nucleic acid components therein are solubilized in the chaotropic salt solution and the solution is incubated with a labelled nucleic acid probe at 20.degree. to 40.degree. C. in the absence of formamide to cause molecular hybridization between the probe and solubilized nucleic acid components, and the molecular hybridization is detected. The chaotropic salt is selected from quanidine thiocyanate, alkali metal perchlorates, alkali metal iodides, alkali metal trifluoroacetates, alkali metal trichloroacetates and alkali metal thiocyanates. The probe may be in solution or immobilized. RNA detected or quantitated may be ribosomal RNA or genomic RNA, and in one embodiment the RNA is HIV viral RNA. When detecting DNA, the solution containing solubilized cells and DNA is heated to at least 45.degree. C.