Tapestation vs Qubit DNA concentration mismatch

Question

We regularly use both a Qubit 4 fluorometer and the TapeStation 4150 to measure DNA concentrations. We follow the recommended procedures for both devices but the TapeStation consistently gives the concentration as 2-4 times lower than the Qubit. The TapeStation concentration measures 200-5000 bp. Does this base pair range exclude enough DNA to account for the lower concentration? Can we do a standard or QC to ensure that the TapeStation measures correctly?

Cendy.D · Answer

Hi Jdgood, 
 
 Thank you for your question. Each TapeStation ScreenTape assay has a corresponding size range and quantitative range. It is important that the appropriate ScreenTape assay is selected dependent on the sample's specifications. Please reference this TapeStation catalogue to review the specifications of each ScreenTape assay: Agilent ScreenTape Consumables and Reagents for the Agilent TapeStation Systems . Additionally, proper assignment of the marker is important as it is used to assess concentration. Generally, if an upper marker is included in the ScreenTape assay, it will be used to assess concentration. Furthermore, if the sample or a contaminant is interfering with the marker used to assess concentration (artificially increasing its signal), then the samples will be reported with a lower concentration. 
 If you still require assistance, please consider contacting us at electrophoresis@agilent.com . Please share raw data files and sample details (sample type, what sample is diluted in and expected concentration and size).