In some examples, a system for amplifying and quantifying a target organism present in a sample includes a detection device configured to amplify and detect a nucleic acid associated with the target organism. The detection device configured to receive a sample and to amplify nucleic acid in the sample over an amplification cycle. The detection device is configured to capture a data set including measurements of the nucleic acid collected during the amplification cycle. The system further includes a computing device configured to receive the data set and to apply a machine learning system to the data set. The machine learning system is trained to estimate a quantity of the target organism present in the sample based on the measurements in the data set.