What could have gone wrong if the CT values are unusually high for all wells in a sample?
One or more of the following 3 issues can lead to high CT values for all wells:
1. The cycling program is incorrect. Please make sure to program the real-time PCR cycler with the temperature profile shown in the protocols.
2. DNA quality is poor. Check the DNA quality using the DNA QC Plate (see the qBiomarker Copy Number PCR Array Handbook) or on an agarose gel to see if the DNA is degraded. If the DNA is not degraded, it could be of insufficient purity. We recommend using one of the kits indicated in Table 3 of the qBiomarker Copy Number PCR Array Handbook for isolation of high-quality DNA.
3. Too little DNA is used. Make sure that the DNA has been properly quantified. During the DNA purification process, it is essential to perform an RNase digestion. RNA contamination in the DNA sample will lead to overestimation of DNA quantity. Note that larger amounts of DNA are recommended when working with FFPE samples.
1. The cycling program is incorrect. Please make sure to program the real-time PCR cycler with the temperature profile shown in the protocols.
2. DNA quality is poor. Check the DNA quality using the DNA QC Plate (see the qBiomarker Copy Number PCR Array Handbook) or on an agarose gel to see if the DNA is degraded. If the DNA is not degraded, it could be of insufficient purity. We recommend using one of the kits indicated in Table 3 of the qBiomarker Copy Number PCR Array Handbook for isolation of high-quality DNA.
3. Too little DNA is used. Make sure that the DNA has been properly quantified. During the DNA purification process, it is essential to perform an RNase digestion. RNA contamination in the DNA sample will lead to overestimation of DNA quantity. Note that larger amounts of DNA are recommended when working with FFPE samples.