What testing should be performed in order to assess the quality of a DNA sample?
FAQ ID — 3424

DNA concentration and purity can be measured by UV spectrophotometry. 

Dilute samples and measure absorbance in 10 mM Tris•Cl, pH 8.0. An absorbance reading of 1.0 at 260 nm in a 1 cm detection path corresponds to a DNA concentration of 50 µg/ml. All DNA samples should meet the following criteria:

1. Concentration, as measured by A260, should be greater than 10 µg/ml
2. A260/A280 ratio should be greater than 1.8
3. A260/A230 ratio should be greater than 1.7

It is also strongly recommended that DNA quality be measured with the DNA QC Plate.
DNA quality and consistency can be checked more reliably with the DNA QC Plate by real-time PCR measuring 7 reference genes. For a detailed procedure, see the qBiomarker Copy Number PCR Array Handbook.