nucleic acid test, any of various tests that use molecular biology techniques to detect and identify microorganisms, including viruses, on the basis of their nucleic acids. It includes culture confirmation tests, which identify organisms grown in culture, and direct tests, which can identify the organisms directly in a specimen. Direct tests can be further subdivided on the basis of whether their target nucleic acids are nonamplified or amplified for the test; the former are based on identification of a unique target sequence by using a labeled probe; the latter are classified as nucleic acid amplification tests.
