about-lod.md
In NACHO: NanoString Quality Control Dashboard

The limit of detection (LoD) is determined by measuring the ability to detect POS_E, the 0.5 fM positive control probe, which corresponds to about 10,000 copies of this target within each sample tube. On a FLEX/MAX system, the standard input of 100 ng of total RNA will roughly correspond to about 10,000 cell equivalents (assuming one cell contains 10 pg total RNA on average). An nCounter assay run on the FLEX/MAX system should thus conservatively be able to detect roughly one transcript copy per cell for each target (or 10,000 total transcript copies). In most (codeset) assays, you will observe that even the POS_F probe (equivalent to 0.25 copies per cell) is detectable above background.