Analytical methods using RNA-containing probes for the detection or analysis of nucleic acid sequences is described. These probes are contacted with a sample suspected of containing the nucleic acid sequence and if they form duplexes, they are hydrolysed. This may be done, for example during an amplification reaction. AMP generated as a result of the hydrolysis is converted to ATP. The ATP may then be detected using bioluminescent reagents. Inclusion of modified adenosine in at least one probe means that the signal arising from one probe will give rise to a different and distinguishable bioluminescent signal thus enabling the use of for example an internal control in bioluminescently-reported nucleic acid tests.