Abstract: A method for determining the presence or absence of variant ribonucleic acid molecules in a population of ribonucleic acid molecules, wherein the reference sequence of the variant ribonucleic acid molecules is known, the method comprising: (a) interrogating the population of ribonucleic acid molecules with a plurality of primer molecules and a plurality of probes so as to saturate the population of ribonucleic acid molecules with the probes and primer molecules such that the probes and primer molecules are adjacent to one another when hybridized to their respective complimentary sequences on the ribonucleic acid molecules, (b) ligating the probes to their respective adjacent primer molecules so as to form ligated nucleic acid molecules, and (c) detecting the presence of ligated nucleic acid molecules that are complementary to a sequence that differs from the reference sequence, thereby determining the presence or absence of one or more variant ribonucleic acid molecules in the population of ribonucleic acid m