Novogene has strict quality control standards; only qualified samples can be used for NGS. Before downstream bioinformatic analysis, quality testing is applied.
We validate the quality of the sample, the library and the data.
Sample Quality Control
To ensure successful library preparation and sequencing, all samples received by Novogene first undergo quality control assessment. DNA samples quality is measured using agarose gel electrophoresis, and Qubit 2.0. RNA sample quality is assessed using NanoDrop, agarose gel electrophoresis, and the Agilent 2100 BioAnalyzer.
Library Quality Control
During NGS library preparation, initial samples will be fragmented/sheared, tailed, ligated with modified oligos, size selected and amplified. Accurate qualification and quantification of the library is crucial to successful sequencing. Novogene library quality control process includes four steps:
- Volume: sample amounts higher than the minimum requirements may improve the library success rate
- Qubit: measures the concentration to ensure that the best amount of material is used to achieve optimal results
- Agilent 2100: provides sizing and quality assessment of the library
- qPCR: measures the concentration of the library and presence of Illumina anchor sequences prior to analysis
If both sample volume and concentration meet specifications, libraries are tested using the Agilent BioAnalyzer and qPCR.
Raw Data Quality Control
QC of raw data is an important measure for determining the quality of the libraries and indicating whether the sequencing succeeded or failed. Novogene will stringently analyze the sequencing data to ensure accuracy and reliability, including quality, error rate, Q20, Q30, adapter contamination rate, etc. Raw reads with low quality, containing adapter sequences, or with >10% of “N” base calls will be removed to obtain the clean reads.
By carefully and diligently controlling the quality of the DNA and RNA that is sequenced we can increase the quality of the results that we pass on to our customers.