: what are positive and negative controls used for in pcr ? and how do they show that there is a contamination in the stuff ?

Question

: what are positive and negative controls used for in pcr ? and how do they show that there is a contamination in the stuff ?

In: Other

Answer 1

Assuming you’re asking about polymerase chain reaction.

As positive control, you use a sample known to contain the locus (stretch of DNA) of interest. As a negative control, you use no sample at all — just dilution buffer.

The positive control should return positive (low Ct) and the negative control should return negative (very high/incalculable Ct). If there’s a contamination that causes false positives in one of your reagents, then that’d probably show up as the negative control not returning negative.