At the end of the run, check the standards to make sure that the replicates reasonably overlap with one another and that there is no amplification in the negative controls. It is not unusual to have outliers or no amplification in some of the lower dilutions. Check the standard curve. Efficiency should be between 90-110%, R2 should be as close to 1 as possible, and error should be as close to 0 as possible. If necessary, outlier standard replicates can be removed in the software to change these values and the samples can be reanalyzed.