The present invention provides systems, methods, and compositions for nucleic acid detection based on non-mass determined base compositions. For example, in certain embodiments, base count data for a template nucleic acid is generated using an approach that does not measure molecular mass of the template nucleic acid (e.g., by sequencing the template nucleic acid) and a database comprising base count entries is queried to identify the target nucleic acid. In particular embodiments, sequencing is employed which is conducted in substantially real-time.