Are there any general recommendations to take into account when performing a nucleic acid extraction?

Yes. Please note that:

• Phenol-based extraction methods should be avoided due to the risk of carrying over phenol to the PCR reaction. Phenol is a strong PCR inhibitor and may lead to false negative results.

• Ethanol – which is a washing buffer component of many extraction systems – should be completely removed prior to the final elution step. When using column-based QIAGEN extraction systems this can readily be achieved by an additional centrifugation after the last washing step (13.000 rpm, 3 min, room temperature). Ethanol is a potent PCR inhibitor and may also lead to false negative results.

• When sample material low in DNA/RNA content is used (e.g. CSF, serum, plasma) QIAGEN strongly recommends to add carrier RNA to the extraction procedure (poly(A) RNA homopolymer, Amersham Biosciences, cat. no.: 27-4110-01). This will increase the overall yield of the DNA/RNA of interest.