A method of processing a plurality of starting samples in parallel, wherein the starting samples have varying concentration of target nucleic acid, the method comprising: conducting a nucleic acid amplification reaction according to a method comprising: a) providing a starting sample comprising a target nucleic acid; b) segmenting at least part of the sample to provide a set of sample droplets in a continuous flow of immiscible carrier fluid through a channel, each of the droplets containing on average one or fewer copies of a target nucleic acid and reagents sufficient to perform a polymerase chain reaction; c) providing a further starting sample comprising the target nucleic acid; d) segmenting at least part of the further sample to provide a set of further sample droplets in the continuous flow of immiscible carrier fluid through the channel, each of the further droplets having a concentration of the target nucleic acid that is higher than the concentration of the target nucleic acid in the droplets and having reagents sufficient to perform a polymerase chain reaction; e) passing the droplets provided in step b) and the further droplets provided in step d) through a plurality of thermal zones thereby allowing the target nucleic acid, if present, to be amplified in each one of the droplets and the further droplets; and f) detecting the presence or absence of, and determining the amount of, the amplified target nucleic acid in the droplets and the further droplets while in the flow, wherein step f) is performed at multiple thermal cycles, thereby monitoring the amount of amplified target nucleic acid throughout the cycles. conducting a nucleic acid amplification reaction according to a method comprising: a) providing a starting sample comprising a target nucleic acid; b) segmenting at least part of the sample to provide a set of sample droplets in a continuous flow of immiscible carrier fluid through a channel, each of the droplets containing on average one or fewer copies of a target nucleic acid and reagents sufficient to perform a polymerase chain reaction; c) providing a further starting sample comprising the target nucleic acid; d) segmenting at least part of the further sample to provide a set of further sample droplets in the continuous flow of immiscible carrier fluid through the channel, each of the further droplets having a concentration of the target nucleic acid that is higher than the concentration of the target nucleic acid in the droplets and having reagents sufficient to perform a polymerase chain reaction; e) passing the droplets provided in step b) and the further droplets provided in step d) through a plurality of thermal zones thereby allowing the target nucleic acid, if present, to be amplified in each one of the droplets and the further droplets; and f) detecting the presence or absence of, and determining the amount of, the amplified target nucleic acid in the droplets and the further droplets while in the flow, wherein step f) is performed at multiple thermal cycles, thereby monitoring the amount of amplified target nucleic acid throughout the cycles. a) providing a starting sample comprising a target nucleic acid; b) segmenting at least part of the sample to provide a set of sample droplets in a continuous flow of immiscible carrier fluid through a channel, each of the droplets containing on average one or fewer copies of a target nucleic acid and reagents sufficient to perform a polymerase chain reaction; c) providing a further starting sample comprising the target nucleic acid; d) segmenting at least part of the further sample to provide a set of further sample droplets in the continuous flow of immiscible carrier fluid through the channel, each of the further droplets having a concentration of the target nucleic acid that is higher than the concentration of the target nucleic acid in the droplets and having reagents sufficient to perform a polymerase chain reaction; e) passing the droplets provided in step b) and the further droplets provided in step d) through a plurality of thermal zones thereby allowing the target nucleic acid, if present, to be amplified in each one of the droplets and the further droplets; and f) detecting the presence or absence of, and determining the amount of, the amplified target nucleic acid in the droplets and the further droplets while in the flow,