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If not done well PCR has an incredibly high false positive rate. If you contaminate your set up area (or equipment) with past PCR amplification material you wil
by danieltillett 7y ago
If not done well PCR has an incredibly high false positive rate. If you contaminate your set up area (or equipment) with past PCR amplification material you will get a very high rate of PCR positivity.
Of course if you do things correctly this shouldn’t happen, but if the average pathology lab technician is as skilled as my ex-students and colleagues (and myself) then I would be not be so keen to rule out false positives.
Yes there is a major issue with false negatives, especially when the swab was not performed or stored correctly. RNA is not very stable and it is very easy to destroy all the viral RNA if you are not careful.
- ImaCake 7y agoI am familiar with these drawbacks, having worked as a research assistant doing RT-PCR and qPCR. My understanding from a brief stint in industry is that there is a lot more quality control to be found in industrial and diagnostic labs than is typically found in a research lab. So I imagine there is still an appreciable amount of false positives even in a diagnostic lab, but they do have a lot more quality control in place to reduce it.
- danieltillett 7y agoYes normally this is the case, but when they are under immense pressure to pump through the samples we should expect the normal high standards drop.