How long does a nanopore channel last during a run?

Individual nanopore channels in a MinION flow cell have a finite lifetime. During a run, pores can become blocked, inactive, or saturated. Typically, a new flow cell starts with most of its 2,048 channels active, but the number of active channels gradually decreases over the course of a run. Oxford Nanopore Technologies specifies a minimum number of active pores per flow cell for quality results. Yenos's protocol accounts for pore channel attrition by running the measurement for a defined period and using the active channel count to normalize the final miRNA quantification. The bracketing calibration standards also correct for pore-to-pore variability within the run.