Hi Dr. Mark, I have asked about the difference in pcr to bdna.I switched doctors recently and in error a pcr was run instead of bdna.of course it came back detectable at 78. Always have been undetectable by bdna.Why does pcr pick up numbers with me that bdna never does...(this has happpened before 2 years ago,same situation but different drugs..)What do you think????I was all set to start my sti, but elected to run a bdna just to see and then continue on bdna to follow my load..Thank you

There may be slightly more variability in the PCR assay down at the lower levels of detection. So in someone who has a "detectable level" that is below 50 (although the assay can't measure this accurately) and not 0, there can be a 2-3 fold (2-3 times) variability in the value.