A target nucleic acid amplification method that uses RNA transcription (RNA polymerase) and DNA synthesis (reverse transcriptase) to produce RNA amplicon from a target nucleic acid. TMA can be used to target both RNA and DNA.

TMA has several other differences in comparison to PCR and LCR:
- TMA is isothermal. A water bath or heat block is used instead of a thermal cycler.
- TMA produces RNA amplicon rather than DNA amplicon. Since RNA is more labile in the laboratory environment than DNA, this helps reduce the possibility of carry-over contamination.
- TMA produces 100-1000 copies per cycle in contrast to PCR and LCR that produce only two copies per cycle. This results in a 10 billion fold increase of copies within about 15-30 minutes.

From: http://www.gen-probe.com