Why should I order my PCR and Extension Oligos from a separate oligo house where I get my Competitor synthesized?
• Most big oligo houses purifies all of their oligos over the same column resulting in the low-level contamination of PCR primers with competitor if the PCR primers are synthesized after the competitor or ordered anytime after the competitor synthesis. We see contamination up to 3+ months after the competitor synthesis to date. This issue has become very apparent for our prenatal diagnostics studies. Primers and competitors should therefore always be ordered from distinct sources if possible. If not, the current recommendation that the PCR primers be ordered first and tested, followed by the ordering of the competitors, must be followed. PCR primers should not be reordered from that oligo house for a very long time.
