In quantitative polymerase chain reaction (qPCR), the limit of detection (LOD) refers to the lowest amount of target nucleic acid that can be reliably detected and distinguished from background noise. It quantifies assay sensitivity and is typically expressed as a concentration value (e.g., copies per milliliter). The LOD is determined by running a series of target dilutions, identifying the point where reliable detection becomes challenging.
When a qPCR result is reported as "below the limit of detection," the target nucleic acid was not detected at a level above the established LOD. If your Ct value is within the LOD range, it means the target is present in your sample at a concentration the assay can reliably detect.
To learn more about LuminUltra's Limit of Detection for each qPCR assay review these assay data sheets: GeneCount Assay Data Sheets
For lab service results, LuminUltra will invoice for results reported below the detection limit.