A method of amplifying and quantitating a specific nucleic acid sequence in a sample using at least one oligonucleotide primer, a supply of nucleotides and optionally a probe complementary to part of the sequence, one of these including a radionuclide. In the presence of a polymerase the reagents form an amplified product based on the specific nucleic acid sequence. The amplified sequence is allowed to bind to a solid material comprising a fluorescer which fluoresces in proximity to the radionuclide and fluorescence is observed as a measure of the specific nucleic acid sequence. The method can be applied to a range of well-known nucleic acid amplification techniques such as the Polymerase Chain Reaction. A variation on the above method allows use of the Ligase Chain Reaction technique.