The invention describes a method of quantitatively detecting specific nucleotide sequences. Said method is essentially characterized in that a single-stranded nucleic acid, particularly mRNA, which has been isolated from a mixture, e.g. a biological sample, is hybridized in solution, with a polynucleotide sequence which is essentially complementary to the sequence to be determined; the nucleic acid is then immobilized on a solid phase, and the amount of bound hybrid is determined. It has proven to be particularly advantageous if the binding to the coated solid phase is accomplished with the aid of the specifically bindable chemical group which is coupled to the sequence to be determined or to the polynucleotide probe sequence via a linker.