Cycles and thresholds

Continuous real-time detection also allows multiple detection thresholds (i.e. the cycle at which product appears) to be set for the same reaction, which can be related to different levels of risk for disease. For most practical (or even experimental) purposes, 35 cycles of amplification is sufficient. Beyond 35 cycles, the rapidly increasing risk of both false-positive and false-negative detection errors outweighs the marginal gains in sensitivity (see the BEEBOOK paper on molecular methods; Evans et al., 2013).